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ObjectiveTo observe the effects of Hedysari Radix polysaccharide on the apoptosis of gastric sinus smooth muscle cells and explore the underlying mechanism via the insulin-like growth factor-1 （IGF-1）/phosphatidylinositol 3-kinase （PI3K）/serine-threonine kinase （Akt） pathway in the rat model of diabetic gastroparesis （DGP）. MethodSixty-two Wistar male rats were randomized into a blank group （n=12） and a modelling group （n=50）. The rat model of DGP was established by small-dose multiple intraperitoneal injections of streptozotocin combined with an irregular high-fat and high-sugar diet for 4 weeks. The modeled rats were randomized into model group， mosapride citrate （1.35 mg·kg-1）， and high-， medium-， and low-dose （200， 100， and 50 mg·kg-1， respectively） Hedysari Radix polysaccharide groups. The rats were administrated with corresponding drugs by gavage， and those in the blank and model groups with equal volumes of pure water by gavage once a day for 8 consecutive weeks. The random blood glucose and body mass were measured every 2 weeks， and gastric emptying rate was calculated. Hematoxylin-eosin （HE） staining was used to observe the pathological changes of smooth muscle in gastric antrum， and terminal deoxynucleoitidyl transferase-mediated nick-end labeling （TUNEL） was employed to detect the apoptosis of smooth muscle cells in the gastric antrum. The expression of IGF-1， phosphorylated （p）-PI3K， and p-Akt in the smooth muscle of gastric sinus tissue was detected by immunohistochemistry. Western blot was employed to determine the protein levels of IGF-1， p-PI3K/PI3K， p-Akt/Akt， B-cell lymphoma-2 （Bcl-2）， and Bcl-2-associated X protein （Bax） in the smooth muscle of the gastric antrum. ResultCompared with the blank group， the model group showed elevated random blood glucose at all time points （P<0.01）， decreased body mass and gastric emptying rate （P<0.01）， increased apoptotic index of smooth muscle cells in the gastric antrum （P<0.01）， down-regulated protein levels of IGF-1， p-PI3K/PI3K， p-Akt/Akt， and Bcl-2， and up-regulated protein level of Bax （P<0.01）. Compared with the model group， the 8 weeks of drug administration lowered the random blood glucose， increased the body mass and gastric emptying rate （P<0.05， P<0.01）， decreased the apoptotic index of smooth muscle cells in the gastric antrum （P<0.05， P<0.01）， up-regulated the protein levels of IGF-1， p-PI3K/PI3K， p-Akt/Akt， and Bcl-2， and down-regulated the protein level of Bax （P<0.05， P<0.01）. Compared with the mosapride citrate group，the administration of low-dose Hedysari Radix polysaccharide for 6 and 8 weeks lowered the random blood glucose and decreased the body mass （P<0.05， P<0.01），low and medium-dose Hedysari Radix polysaccharide decreased the gastric emptying rate and the apoptotic index of smooth muscle cells in the astragaloside low-dose group decreased （P<0.05）. The protein levels of IGF-1，p-PI3K/PI3K，p-Akt/Akt and Bcl-2（low dose）were down-regulated and the protein level of Bax was up-regulated by low doses of Hedysari Radix polysaccharide （P<0.05， P<0.01）. Compared with high-dose Hedysari Radix polysaccharide， low-dose Hedysari Radix polysaccharide elevated random blood glucose and reduced body mass after 6 and 8 weeks of administration （P<0.05， P<0.01）， and the low and medium doses decreased the gastric emptying rate， increased the apoptotic index of smooth muscle cells in the gastric antrum （P<0.05， P<0.01）， down-regulated the protein levels of IGF-1， p-PI3K/PI3K， p-Akt/Akt， and Bcl-2， and up-regulated the protein level of Bax （P<0.05， P<0.01）. Compared with the medium-dose group，the low-dose group of Hedysari Radix polysaccharide had lower body mass，lower gastric emptying rate in rats，higher apoptotic index of smooth muscle cells in gastric sinus tissue after 6 and 8 weeks of administration （P<0.05， P<0.01）， and lower protein expression of IGF-1，p-PI3K/PI3K，p-Akt/Akt. ConclusionHedysari Radix polysaccharide protects the smooth muscle cells in gastric antrum against apoptotic injury and promotes gastric motility by activating the IGF-1/PI3K/Akt signaling pathway， as manifested by the up-regulated expression of IGF-1， p-PI3K， p-Akt， and Bcl-2 and down-regulated expression of Bax.
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Objective:To study the effect of Baihutang on blood glucose， blood lipid metabolism and vascular remodeling in type 2 diabetic rats and its regulation on insulin receptor substrate-1（IRS-1）/ phosphatidylinositol-3 kinase（PI3K）/ protein kinase B（Akt） signal pathway. Method:The 90 rats were randomly divided into normal group， model group， Baihutang low， middle and high dose groups and metformin group， with 15 rats in each group. Except for normal group， the other rats were injected intraperitoneally with streptozotocin to establish the model of type 2 diabetes. The rats in the low， middle and high dose groups were given Baihutang formula granules of 5， 10， 20 g·kg-1 respectively according to their body weight. The positive control group was given metformin （100 mg·kg-1） by intragastric administration， while those in the control group and model group were given the same amount of normal saline once a day for 12 weeks. The levels of fasting blood glucose， glycosylated hemoglobin， serum tumor necrosis factor-α（TNF-α）， interleukin-6（IL-6）， interleukin-1 β（IL-1β）， total cholesterol（TC）， triglyceride（TG） and low-density lipoprotein cholesterol（LDL-C） were measured after administration. The levels of sterol regulatory element binding protein 1C （SREBP1C）， acetyl CoA carboxylase （ACC）， fatty acid synthase gene （FASN） and carnitine palmitoyl transferase 1A （CPT1A）， acylcoa oxidase 1（ACOX1）， recombinant human acylcoa dehydrogenase （ACADM） mRNA in liver of rats were detected by Real-time fluorescence quantitative polymerase chain reaction（Real-time PCR）， Western blot was used to detect the protein levels of IRS-1， PI3K and Akt in liver of rats. Hematoxylin-eosin（HE） staining was used for histopathological examination of rat thoracic aortic vessels. The migration ability of vascular smooth muscle cells in rat thoracic aorta was detected by scratch test. Result:Compared with the normal group， the fasting blood glucose， glycosylated hemoglobin， serum TNF-α， IL-6，IL-1β， TC，TG and LDL-C levels， liver lipid synthesis gene mRNA level and vascular smooth muscle cell migration ability of thoracic aorta in model group were significantly higher than those in normal group （P<0.05）， while fatty acid oxidation gene mRNA level and IRS-1，PI3K，Akt protein level in liver were significantly decreased in model group （P<0.05）. The vascular wall thickness of thoracic aorta increased significantly in rats （P<0.05）. Compared with model group， the levels of fasting blood glucose， glycosylated hemoglobin， serum TNF-α，IL-6， IL-1β， TC， TG and LDL-C， the level of lipid synthesis gene mRNA in liver and the migration ability of vascular smooth muscle cells in thoracic aorta of rats in all Baihutang groups were significantly lower than those in model group （P<0.05）. The mRNA level of fatty acid oxidation gene and the protein levels of IRS-1， PI3K and Akt in liver were significantly increased（P<0.05）， and the histopathology of thoracic aorta was significantly improved and the vascular wall thickness decreased significantly（P<0.05）. Conclusion:Baihutang can reduce the levels of blood glucose， blood lipid and serum inflammatory factors in type 2 diabetic rats， regulate the expression of genes related to lipid metabolism in liver， and improve the histopathology and vascular remodeling of thoracic aorta. The mechanism may be related to the regulation of IRS-1/PI3K/Akt signal pathway.
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Objective:To evaluate the relationship between the mechanism of protective effect of hydromorphone postconditioning on myocardium and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway-mediated autophagy in rats.Methods:Forty healthy male Sprague-Dawley rats, weighing 220-250 g, were divided into 5 groups ( n=8 each) using a random number table method: sham operation group (Sham group), ischemia-reperfusion (I/R) group (group IR), hydromorphone postconditioning group (group HP), PI3K inhibitor group (group W) and hydromorphone postconditioning+ PI3K inhibitor group (group HP+ W). Myocardial ischemia was induced by 30 min occlusion of left anterior descending branch of coronary artery followed by 120 min reperfusion.In group HP, hydromorphone 0.1 mg/kg was injected via femoral vein at 5 min before reperfusion in group HP.In group HP+ W, hydromorphone 0.1 mg/kg and wortmannin (PI3K inhibitor) 15 μg/kg were injected via femoral vein at 5 min before reperfusion.In group W, wortmannin 15 μg/kg was injected via femoral vein at 5 min before reperfusion.At the end of reperfusion, the myocardial infarct size (IS) was determined by TTC staining, the activities of serum lactate dehydrogenase (LDH) was detected by colorimetry, myocardial specimens were collected for microscopic examination of the ultrastructure (with a electron microscope), the expression of phosphorylated Akt (p-Akt) and microtubule-associated protein 1 light chain 3 (LC3) was determined by Western blot and the ratio of LC3-Ⅱ/Ⅰwas calculated. Results:Compared with Sham group, IS and the activities of serum of LDH were significantly increased, p-Akt expression in myocardial tissues was up-regulated, the ratio of LC3-Ⅱ/Ⅰwas increased ( P<0.05), autophagic vacuoles were increased and the damage of ultrastructure of cardiomyocytes was obvious in group IR.Compared with group IR, IS and the activities of serum of LDH were significantly decreased, p-Akt expression in myocardial tissues was up-regulated, the ratio of LC3-Ⅱ/Ⅰwas decreased ( P<0.05), autophagic vacuoles were decreased and the damage of ultrastructure of cardiomyocytes was attenuated in group HR.Compared with group HR, IS and the activities of serum of LDH were significantly increased, p-Akt expression in myocardial tissues was down-regulated, the ratio of LC3-Ⅱ/Ⅰwas increased ( P<0.05), autophagic vacuoles were increased and the damage of ultrastructure of cardiomyocytes was aggravated in group HR+ W. Conclusion:The mechanism of protective effect of hydromorphone postconditioning on myocardium is related to activation of PI3K/Akt signaling pathway and inhibition of autophagy in rats.
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Objective:To investigate the effect of atorvastatin preconditioning on intestinal ischemia-reperfusion (I/R) injury in mice and the relationship with phosphatidylinositol 3-kinase (PI3K)/serine-threonine kinase (Akt) signaling pathway.Methods:Twenty-four healthy male C57BL/6 mice, aged 6-8 weeks, weighing 18-22 g, were divided into 4 groups ( n=6 each) using a random number table method: sham operation group (S group), I/R group, atorvastatin preconditioning group (A group), atorvastatin plus PI3K inhibitor LY294002 group (AL group). Atorvastatin 10 mg/kg was given by intragastric gavage for 3 consecutive days in A and AL groups, and in addition LY294002 0.3 mg/kg was intraperitoneally injected at 30 min before the last administration of atorvastatin in AL group.Intestinal I/R was produced by occlusion of superior mesenteric artery (SMA) for 45 min followed by 2 h reperfusion in anesthetized mice.The superior mesenteric artery was only isolated but not clamped in S group.The mice were sacrificed at the end of reperfusion, and small intestinal tissues were taken for determination of the pathological changes with a light microscope after HE staining and for determination of wet to dry weight ratio(W/D ratio) and expression of PI3K, phosphorylated Akt (p-Akt), autophagy-related proteins Beclin-1, microtubule-associated protein 1 light chain 3Ⅰ (LC3Ⅰ) and LC3Ⅱ.The intestinal damage was assessed and scored according to Chiu.The ratio of LC3Ⅱ expression to LC3Ⅰ expression (LC3Ⅱ/LC3Ⅰ) was calculated. Results:Compared with S group, Chiu′s scores and W/D ratio were significantly increased, the expression of PI3K and p-Akt was down-regulated, the expression of Beclin-1 was up-regulated, and LC3Ⅱ/LC3Ⅰ ratio was increased in I/R, A and AL groups ( P<0.05). Compared with I/R group, Chiu′s scores and W/D ratio were significantly decreased, the expression of PI3K and p-Akt was up-regulated, the expression of Beclin-1 was down-regulated, and LC3Ⅱ/LC3Ⅰ ratio was decreased in A group ( P<0.05). Compared with A group, Chiu′s scores and W/D ratio were significantly increased, the expression of PI3K and p-Akt was down-regulated, the expression of Beclin-1 was up-regulated, and LC3Ⅱ/LC3Ⅰ ratio was increased in AL group ( P<0.05). Conclusion:Atorvastatin preconditioning can mitigate intestinal I/R injury in mice, and the mechanism is related to activating PI3K/Akt signaling pathway and inhibiting the level of autophagy.
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Objective@#To evaluate the role of phosphatidylinositol-3-kinase/protein kinase B/nuclear factor erythroid 2-related factor 2 (PI3K/Akt/Nrf2) signaling pathway in resveratrol preconditioning-induced cardioprotection in diabetic rats.@*Methods@#Clean-grade healthy male Sprague-Dawley rats, aged 2-3 months, weighing 240-280 g, were used in the study.The diabetes model was established by intraperitoneal injection of streptozotocin 30 mg/kg once a day for 7 consecutive days.Forty diabetic rats were selected and divided into 4 groups (n=10 each) according to the random number table method: sham operation group (S group), myocardial ischemia-reperfusion (I/R) group (I/R group), resveratrol plus myocardial I/R group (Res+ I/R group), and PI3K inhibitor LY294002 plus resveratrol plus myocardial I/R group (LY+ Res+ I/R group). The myocardial I/R injury model was established by ligating the left anterior descending coronary artery for 30 min followed by 120-min reperfusion in anesthetized rats.Resveratrol 20 mg/kg was intraperitoneally injected once a day for 7 consecutive days at one week before surgery in Res+ I/R and LY+ Res+ I/R groups.LY294002 1.5 mg/kg was intraperitoneally injected at 30 min before operation in LY+ Res+ I/R group.After 120 min of reperfusion, blood samples were taken for determination of serum creatine kinase-MB (CK-MB) and lactic dehydrogenase (LDH) concentrations (by enzyme-linked immunosorbent assay), and myocardial tissues at the ischemic area were obtained for determination of superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA)levels (by enzyme-linked immunosorbent assay) and expression of Akt, phosphorylated Akt (p-Akt), glycogen synthase kinase 3β (GSK3β), phosphorylated GSK3β (p-GSK3β) and Nrf2 (by Western blot).@*Results@#Compared with group S, serum CK-MB and LDH concentrations were significantly increased, the SOD and GSH levels were decreased, the MDA level was increased, and the expression of p-Akt and p-GSK3β was down-regulated in I/R group (P<0.05). Compared with I/R group, serum CK-MB and LDH concentrations were significantly decreased, the SOD and GSH levels were increased, the MDA level was decreased, and the expression of p-Akt, p-GSK3β and Nrf2 was up-regulated in Res+ I/R group (P<0.05). Compared with Res+ I/R group, serum CK-MB and LDH concentrations were significantly increased, the SOD and GSH levels were decreased, the MDA level was increased, and the expression of p-Akt, p-GSK3β and Nrf2 was down-regulated in LY+ Res+ I/R group (P<0.05).@*Conclusion@#The mechanism of resveratrol preconditioning-induced cardioprotection is related to activating PI3K/Akt/Nrf2 signaling pathway and inhibiting oxidative stress responses in diabetic rats.
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Objective To evaluate the role of phosphatidylinositol 3-kinase/serine-threonine kinase (PI3K/Akt) signaling pathway in propofol-induced inhibition of migration and invasion ability of human nonsmall cell lung cancer H1975 cells.Methods H1975 cells were divided into 4 groups (n=36 each) using a random number table method:control group (group C),20 μg/ml propofol group (group P),0.5 ng/ml PI3K/Akt signaling pathway activator insulin-like growth factor 1 (IGF-1) group (group IGF-1),and 20 μg/ml propofol plus 0.5 ng/ml IGF-I group (group P+IGF-1).The migration and invasion ability of H1975 cells was determined by wound healing assay and Transwell invasion assay,respectively.The expression of phosphorylated Akt (p-Akt) and matrix metalloproteinase-9 (MMP-9) was assessed by Western blot.Results Compared with group C,and the ability of migration and invasion was significantly reduced,and the expression of p-Akt and MMP-9 was down-regulated in group P,and the ability of migration and invasion was significantly enhanced,and the expression of p-Akt and MMP-9 was up-regulated in group IGF-1 (P＜0.05).Compared with group P,the ability of migration and invasion was significantly enhanced,and the expression of p-Akt and MMP-9 was up-regulated in group P+IGF-1 (P＜0.05).Compared with group IGF-1,the ability of migration and invasion was significantly reduced,and the expression of p-Akt and MMP-9 was down-regulated in group P+IGF-1 (P＜0.05).Conclusion The mechanism by which propofol inhibits migration and invasion ability of human non-small cell lung cancer H1975 cells is related to blocking PI3K/Akt signaling pathway.
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Objective To study the effect of insulin on phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway in diabetic rats with myocardial ischemia reperfusion injury.Methods Diabetic rats were induced by high-sugar and high-fat diet plus intraperitoneal injection of streptozotocin (40 mg/kg).They were randomly divided into diabetic sham group (group A),diabetes ischemic reperfusion group (group B),diabetes ischemic reperfusion insulin treatment group (group C) and diabetic ischemia reperfusion + insulin Wortmaninn (PI3K inhibitors) group (group D),10 in each group.Myocardial ischemia reperfusion model in diabetic rats:heart was exposed between the third and fourth ribs of the left chest,2 mm from the lower edge of the left atrial ear,and 5-0 sterile suture was used to ligate the anterior descending coronary artery (LAD) and the great cardiac vein for 30 min,and then the perfusion was resumed for 120 min.Wortmannin (15 μg/kg) was given through femoral vein 20 min before ligation in group D,and the same amount of normal saline was given in the other 3 groups.Insulin (2 U/kg) was injected subcutaneously in group C and D 10 min before ligation,and the same amount of normal saline was injected subcutaneously in group A and group B.Plasma creatine kinase MB (CK-MB)and troponin Ⅰ (cTnⅠ) levels were measured in arterial blood after 120 min of reperfusion,and PI3K and Akt expression in myocardial tissue were detected by Western blot.Results Compared with the group A,the plasma levels of cTnI and CK-MB increased and the expressions of PI3K and phosphorylated protein kinase B (p-Akt) in myocardium decreased in the group B (P ＜ 0.05).After insulin treatment,the plasma cTnI [(0.89 ± 0.26) μg/L],CK-MB [(9.24 ±3.16) μg/L] in the myocardial tissue of the group C decreased,while the expression of PI3K (0.341 8 ±0.03 1) and p-Akt (0.673 1 ±0.028) in the myocardial tissue increased (P ＜0.05).After insulin + Wortmaninn administration,the plasma cTnI [(1.16 ±0.29) μg/L] and CK-MB [(12.57 ± 3.01) μg/L] in the group D increased,while the expression of PI3K (0.292 7 ± 0.036) and p-Akt (0.531 4 ± 0.030) in the myocardial tissue decreased,with statistically significant difference (P ＜ 0.05).Conclusions Insulin can reduce serum CK-MB and cTnⅠ levels in diabetic rats with myocardial ischemia reperfusion injury,possibly by activating PI3K/Akt signal transduction pathway,inhibiting myocardial enzyme release,and improving myocardial ischemia reperfusion injury in diabetic rats to play a protective role in myocardial cells.
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Objective To evaluate the role of PI3K∕Akt signaling pathway in dexmedetomidine-in-duced reduction of lung ischemia-reperfusion ( I∕R ) injury in rats undergoing cardiopulmonary bypass (CPB). Methods Twenty-four healthy adult male Sprague-Dawley rats, weighing 350-450 g, were di-vided into 3 groups (n＝8 each) using a random number table method: group I∕R, dexmedetomidine group ( group D) and dexmedetomidine plus wortmannin group (group D+W). Rats were anesthetized with pento-barbital sodium. Lung I∕R was induced by clamping the left hilum of lung for 60 min starting from 10 min of CPB, followed by 120-min reperfusion. Dexmedetomidine was injected via the tail vein in a dose of 3 μg∕kg at 10 min before clamping the left hilum of lung, followed by a continuous infusion of 1. 5 μg·kg-1·h-1 until the end of CPB in group D. Dexmedetomidine was injected via the tail vein in a dose of 3 μg∕kg at 10 min before clamping the left hilum of lung, followed by a continuous infusion of 1. 5 μg·kg-1·h-1until the end of CPB, and wortmannin was simultaneously injected via the tail vein in a dose of 15 μg∕kg, fol-lowed by a continuous infusion of 2. 0 μg·kg-1·min-1until the end of CPB in group D+W. Arterial blood samples were collected immediately before CPB ( T1), immediately after opening the left hilum of lung (T2) and at 1. 5 h after the end of CPB (T3), and oxygenation index (OI) and respiratory index (RI) were calculated. The rats were sacrificed at T3, and the left lung was removed for examination of the patho-logical changes which were scored and for determination of apoptosis rate ( by flow cytometry) and Akt, Bad, activated caspase-3, phosphorylated Akt ( p-Akt) and phosphorylated Bad ( p-Bad) in lung tissues ( by Western blot). Results Compared with the baseline at T1, OI was significantly decreased and RI was increased at T2and T3in the three groups (P＜0. 05). OI was significantly decreased and RI was increased at T3than at T2in the three groups ( P＜0. 05). Compared with group I∕R, OI was significantly increased and RI was decreased at T3, the pathological damage score and apoptosis rate were decreased, ratios of p-Akt∕Akt and p-Bad∕Bad were increased, and the expression of activated caspase-3 was down-regulated in group D, and OI was significantly decreased and RI was increased at T2in group D+W ( P＜0. 05). Com-pared with group D, OI was significantly decreased and RI was increased at T3, the pathological damage score and apoptosis rate were increased, ratios of p-Akt∕Akt and p-Bad∕Bad were decreased, and the ex-pression of activated caspase-3 was up-regulated in group D+W ( P＜0. 05). Conclusion Dexmedetomi-dine can reduce dexmedetomidine-induced reduction of lung I∕R injury through activating PI3K∕Akt signa-ling pathway and inhibiting cell apoptosis in rats undergoing CPB.
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Objective To evaluate the role of phosphatidylinositol 3-kinase/serine-threonine kinase(PI3K/Akt) signaling pathway in mitochondrial fission in endotoxin-challenged alveolar type Ⅱ epithelial cells of rats.Methods Rat alveolar type Ⅱ epithelial cells CCL-149 were seeded in 6-well plates at a density of 2×105 cells/ml.CCL-149 cells were divided into 6 groups (n =10 each) using a random number table:control group (group C),lipopolysaccharide (LPS) group (group L),LPS plus CO-releasing molecule-2 (CORM-2) group (group L+CO),LPS plus PI3K inhibitor LY294002 group (group L+LY),LPS plus iCORM-2 group (group L+iCO) and LPS plus dimethyl sulfoxide (DMSO) group (group L+D).CCL149 cells were stimulated with 10 μg/ml LPS for 24 h in L,L+CO,L+LY,L+iCO and L+D groups.CORM-2 100 μmol,LY294002 25 μg and iCORM-2 100 μmol were added at 1 h before stimulation with LPS in L+CO,L+LY and LPS+iC0 groups,respectively.In group L+D,0.1％ DMSO 100 μmol was added at 1 h before stimulation with LPS.After the end of incubation,the concentrations of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the culture medium were determined by enzyme-linked immunosorbent assay,and the expression of phosphorylated-Akt (p-Akt),heme oxygenase-1 (HO-1),dynamin-related protein 1 (Drpl) and fissionl (Fisl) was detected by Western blot.Results Compared with group C,IL-6 and TNF-α concentrations in the culture medium were significantly increased,and the expression ofp-Akt,HO-1,Drp1and FIS1 was up-regulated in L,L+CO,L+LY,L+iCO and L+D groups (P＜0.05).Compared with group L,IL-6 and TNF-α concentrations in the culture medium were significantly decreased,the expression of p-Akt and HO-1 was up-regulated,and the expression of Drp1 and Fis1 was down-regulated in group L+CO,and IL-6 and TNF-α concentrations in the culture medium were significantly increased,the expression of p-Akt and HO-l was down-regulated,and the expression of Drpl and Fisl was up-regulated in group L+LY (P＜0.05).Conclusion Activation of PI3K/Akt signaling pathway can inhibit mitochondrial fission in endotoxin-challenged alveolar type Ⅱ epithelial cells of rats.
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Objective To evaluate the role of hippocampal phosphatidylinositol 3-kinase/serinethreonine kinase/glycogen synthase kinase-3 beta (PI3K/Akt/GSK-3β) signaling pathway in dexmedetomidine-induced reduction of long-term cognitive decline caused by propofol in neonatal rats.Methods A total of 110 clean healthy male Sprague-Dawley rats,aged 7 days,weighing 10-15 g,were divided into 11 groups (n=10 each) using a random number table:normal saline group (NS group),fat emulsion group (F group),10％ dimethyl sulfoxide (DMSO) group (D2 group),dexmedetomidine group (DEX group),TDZD-8 group (TDZD group),10％ DMSO group (D1 group),LY294002 group (LY group),propofol group (P group),dexmedetomidine plus propofol group (PD group),LY294002 plus dexmedetomidine plus propofol group (LYPD group) and TDZD-8 plus dexmedetomidine plus propofol group (TDPD group).Normal saline,fat emulsion,10％ DMSO 100 μl,dexmedetomidine 75 μg/kg and TDZD-8 1 mg/kg were intraperitoneally injected in NS,F,D2,DEX and TDZD groups,respectively.10％ DMSO 5 μ1 and LY294002 25 μg/5 μl were injected via the lateral cerebral ventricle in D1 and LY groups,respectively.Propofol 50 mg/kg was intraperitoneally injected,and an increment of propofol 50 mg/kg was given after recovery of righting reflex in group P.Dexmedetomidine 75 μg/kg was intraperitoneally injected and 30 min later propofol was injected in group PD.LY294002 was injected,30 min later dexmedetomidine was injected,and 30 min later propofol was injected in group LYPD.In group TDPD,TDZD-8 was injected and the other treatment was similar to those previously described in group LYPD.Then the rats were fed to 9 weeks old after returning to the state of consciousness.Morris water maze test was performed to evaluate the cognitive function.Rats were then sacrificed and their hippocampi were harvested for detection of the expression of PI3K,Akt,GSK-3β and PSD95 mRNA (using real-time polymerase chain reaction) and expression of Akt,pAkt(ser473),GSK-3β,pGSK-3β(ser9) and PSD95 (by Western blot).Results Compared with NS group,the escape latency was significantly prolonged,the number of crossing the original platform was reduced,the expression of PI3K,Akt and PSD95 mRNA was down-regulated,the expression of GSK-3β mRNA was up-regulated,p-Akt(ser473)/Akt ratio was decreased,the expression of PSD95 was downregulated,and pGSK-3β (ser9)/GSK-3β ratio was increased in P group (P＜ 0.05).Compared with P group,the escape latency was significantly shortened and the number of crossing the original platform was increased in PD,LYPD and TDPD groups,the expression of PI3K,Akt and PSD95 mRNA was up-regulated,and the expression of GSK-3β mRNA was down-regulated in PD group,and pAkt(ser473)/Akt ratio was increased,the expression of PSD95 was up-regulated,and pGSK-3β (ser9)/GSK-3β ratio was decreased in PD and TDPD groups(P＜0.05).Compared with PD group,the escape latency was significantly prolonged,the number of crossing the original platform was reduced,the expression of GSK-3β mRNA was up-regulated,the expression of PSD95 mRNA was down-regulated,pAkt (ser473)/Akt ratio was decreased,the expression of PSD95 was down-regulated,and pGSK-3β (ser9)/GSK-3β ratio was increased in LYPD group,and the escape latency was significantly shortened,the number of crossing the original platform was increased,the expression of GSK-3β mRNA was down-regulated,the expression of PSD95 mRNA was up-regulated,pGSK-3β(ser9)/GSK-3β ratio was decreased,and the expression of PSD95 was up-regulated in TDPD group(P＜0.05).Conclusion Hippocampal PI3K/Akt/GSK-3β signaling pathway is involved in dexmedetomidine-induced reduction of long-term cognitive decline caused by propofol in neonatal rats.
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Objective To evaluate the role of hippocampal phosphatidylinositol 3-kinase∕serine-threonine kinase (PI3K∕Akt) signaling pathway in exogenous orexin A-induced improvement of isoflurane anesthesia-caused decline in memory function of mice. Methods A total of 100 pathogen-free healthy adult male C57BL∕6 mice, aged 8-12 weeks, weighing 20-25 g, in which the lateral ventricle was catheter-ized, were divided into 5 groups (n = 20 each) using a random number table: control group (group C), isoflurane group (group I), orexin A group (group OA), orexin A plus dimethyl sulfoxide group (group OA+D) and orexin A plus PI3K inhibitor LY294002 group (group OA+LY). Normal saline was administra-ted in group C and group I. Orexin A 1. 5 mmol∕L was given in group OA. Orexin A 1. 5 mmol∕L (dissolved in dimethyl sulfoxide) was given in group OA+D. Orexin A 1. 5 mmol∕L and LY29400210 mmol∕L were given in group OA+LY. Group C only inhaled pure oxygen for 2 h (oxygen flow rate 2 L∕min), all the rest groups inhaled 1. 4％ isoflurane for 2 h, and the corresponding drug 2 μl was injected into the lateral cere-bral ventricle according to the concentration mentioned above at 15 min before the end of anesthesia. Twelve mice were randomly selected from each group and trained for contextual fear conditioning test, and then fear memory retrieval was conducted at 24 h after training. The rest 8 mice in each group were sacrificed at 2 h after the end of anesthesia and their brains were removed for determination of the expression of PI3K, Akt and phosphor-Akt (p-Akt) protein by Western blot. Results Compared with group C, the freezing time was significantly shortened, the expression of PI3K, Akt and p-Akt was down-regulated, and p-Akt∕Akt ratio was decreased in group I (P<0. 05). Compared with group I, the freezing time was significantly pro-longed, the expression of PI3K, Akt and p-Akt was up-regulated, and p-Akt∕Akt ratio was increased in group OA (P<0. 05). There was no significant difference in each parameter mentioned above between group OA and group OA+D (P>0. 05). Compared with group OA+D, the freezing time was significantly short-ened, the expression of PI3K, Akt and p-Akt was down-regulated, and p-Akt∕Akt ratio was decreased in group OA+LY (P<0. 05). Conclusion Hippocampal PI3K∕Akt signaling pathway is involved in exoge-nous orexin A-induced improvement of isoflurane anesthesia-caused decline in memory function of mice.
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Objective To evaluate the relationship between phosphatidylinositol 3?kinase∕serine?threonine kinase(PI3K∕Akt)signaling pathway and autophagy during acute lung injury in septic mice. Methods Thirty?six male C57BL∕6 mice, aged 6-8 weeks, weighing 20-25 g, were divided into 3 groups(n=12 each)using a random number table: sham operation group(group SH), sepsis group (group S)and PI3K inhibitor LY294002 plus sepsis group(group LY+S). Sepsis was induced by cecal ligation and puncture in S and LY+S groups. LY294002 30 mg∕kg was intraperitoneally injected at 2 h be?fore operation in group LY+S. Arterial blood samples were taken at 24 h after operation for blood gas analy?sis, PaO2was recorded, and oxygenation index was calculated. Lung specimens were obtained for examina?tion of pathological changes which were scored and for determination of autophagosome count(using trans?mission electron microscope), wet∕dry weight ratio(W∕D ratio)and expression of Akt, phosphorylated Akt(p?Akt), Beclin?1 and microtubule?associated protein 1 light chain 3 Ⅱ(LC3 Ⅱ). The p?Akt∕Akt ratio was calculated. Results Compared with group SH, oxygenation index was significantly decreased,and the W∕D ratio and pathological score were increased in S and LY+S groups, the autophagosome count was significantly increased, p?Akt∕Akt ratio was increased, and the expression of Beclin?1 and LC3Ⅱ was up?regulated in group S(P<0.05). Compared with group S, oxygenation index was significantly de?creased, and the W∕D ratio was increased, the autophagosome count was decreased, pathological scores were increased, p?Akt∕Akt ratio was decreased, and the expression of Beclin?1 and LC3Ⅱwas down?regu?lated in group LY+S(P<0.05). Conclusion PI3K∕Akt signaling pathway activation mediates autophagy and is involved in the endogenous protective mechanism of acute lung injury in septic mice.
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Objective To evaluate the role of phosphatidylinositol 3?kinase(PI3K)∕serine?threo?nine kinase(Akt)signaling pathway in propofol?induced invasion of human liver cancer cell line HepG2. Methods HepG2 cells were cultured in RPMI 1640 medium supplemented with 10% fetal bovine serum in a 5% CO2incubator at 37℃. HepG2 cells at the logarithmic growth phase were divided into 6 groups(n=18 each)using a random number table: control group(group C), propofol group(group P), PI3K∕Akt signaling pathway agonist IGF?1 group(group IGF), PI3K∕Akt signaling pathway inhibitor LY294002 group(group LY), IGF?1 plus propofol group(group IGF+P)and LY294002 plus propofol group (group LY + P). Propofol 120 μg∕ml was added in group P. IGF?1 10 nmol∕L was added in group IGF. LY294002 10 μmol was added in group LY. In group IGF+P, 10 nmol∕L IGF?1 was added, cells were in?cubated for 24 h, and then 120 μg∕ml propofol was added. In group LY+P, 10 μmol LY294002 was add?ed, cells were incubated for 24 h, and then 120 μg∕ml propofol was added. The invasion of cells was measured by Transwell invasion assay at 24 h of incubation. The expression of PI3K and Akt mRNA in cells was determined by real?time polymerase chain reaction. The expression of Akt, PI3K and phosphorylated Akt(p?Akt)was detected by using Western blot. Results Compared with group C, the invasive cell count was significantly reduced, the expression of PI3K protein and mRNA was down?regulated, p?Akt∕Akt ratio was decreased, and the expression of Akt mRNA was down?regulated in P, P+IGF, LY and P+LY groups, and the invasive cell count was significantly increased, the expression of PI3K protein and mRNA was up?regulated, p?Akt∕Akt ratio was increased, and the expression of Akt mRNA was up?regulated in group IGF(P<0.05). Compared with group P, the invasive cell count was significantly increased, the expression of PI3K protein and mRNA was up?regulated, p?Akt∕Akt ratio was increased, and the expres?sion of Akt mRNA was up?regulated in group P+IGF, and the invasive cell count was significantly reduced, the expression of PI3K protein and mRNA was down?regulated, p?Akt∕Akt ratio was decreased, and the ex?pression of Akt mRNA was down?regulated in group P+LY(P<0.05). The invasive cell count was signifi?cantly reduced, the expression of PI3K protein and mRNA was down?regulated, p?Akt∕Akt ratio was de?creased, and the expression of Akt mRNA was down?regulated in group P+IGF as compared with group IGF (P<0.05)and in group P+LY as compared with group LY(P<0.05). Conclusion The mechanism by which propofol inhibits invasion of HepG2 cells is related to inhibiting activation of PI3K∕Akt signaling path?ways.
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Objective To evalute the role of phosphatidylinositol 3?kinase(PI3K)∕serine?threo?nine kinase(Akt)∕endothelial nitric oxide synthase(eNOS)signaling pathway in sevoflurane postcondi?tioning?induced attenuation of brain injury in a rat model of hemorrhagic shock and resuscitation(HSR). Methods Seventy?two pathogen?free healthy adult male Sprague?Dawleg rats, weighing 300-350 g, were divided into 4 groups(n=18 each)using a random number table: sham operation group(group S), group HSR, sevoflurane postconditioning group(group SP)and sevoflurane postconditioning plus PI3K∕Akt signaling pathway specific inhibitor wortmannin group(group SP+WT). Hemorrhagic shock was in?duced by withdrawing blood(40% of the total blood volume)from the right common carotid artery over an interval of 30 min, and 1 h later the animals were resuscitated with infusion of the shed blood via the left jugular vein over 30 min. In group SP+WT, wortmannin 0.6 mg∕kg was administrated via the jugular vein at 30 min before establishment of the model. In SP and SP+WT groups, 2.4% sevoflurane was inhaled for 30 min starting from the onset of infusion of the shed blood. At 10 min before withdrawing blood(T0), im?mediately after the end of withdrawing blood(T1), at 30 min and 1 h after the end of withdrawing blood (T2,3)and immediately after infusion of the shed blood(T4), blood samples from the common carotid ar?tery were collected for blood gas analysis, the blood lactate concentration was recorded, and mean arterial pressure was simultaneously recorded. At 24 h after infusion of the shed blood, 6 rats were randomly select?ed from each group and sacrificed, and their brains were immediately removed for determination of cerebral infarct volume(by TTC staining), expression of hippocampal caspase?3(by immuno?histochemistry), and expression of Akt, phosphorylated Akt(p?Akt)and eNOS(by Western blot). The ratio of p?Akt∕Akt was calculated. Results Compared with group S, the mean arterial pressure was significantly decreased and the blood lactate concentration was increased at T1?3, the cerebral infarct volume was increased, and the expression of caspase?3 was up?regulated in the other three groups, and the ratio of p?Akt∕Akt was sig?nificantly increased, and eNOS expression was up?regulated in group SP(P<0.05). Compared with group HSR, the cerebral infarct volume was significantly decreased, the expression of caspase?3 was down?regula?ted, the ratio of p?Akt∕Akt was increased, and eNOS expression was up?regulated in group SP(P<0.05). Compared with group SP, the cerebral infarct volume was significantly increased, the expression of caspase?3 was up?regulated, the ratio of p?Akt∕Akt was decreased, and eNOS expression was down?regula?ted in group SP+WT(P<0.05). Conclusion PI3K∕Akt∕eNOS signaling pathway activation mediates sevoflurane postconditioning?induced attenuation of brain injury in a rat model of HSR.
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Objective To evaluate the effect of methylprednisolone on endoplasmic reticulum stress in rats with ventilator-induced lung injury ( VILI ) and the relationship with phosphatidylinositol 3-kinase∕serine-threonine protein kinase ( PI3K∕Akt) signaling pathway. Methods One hundred clean-grade male Sprague-Dawley rats, aged 4-5 months, weighing 270-320 g, were divided into 5 groups ( n=20 each) using a random number table method: control group ( C group) , VILI group ( V group) and different doses of methylprednisolone groups ( M1-3 groups) . Group C received no mechanical ventilation and kept spontane-ous breathing for 4 h. Rats were mechanically ventilated ( tidal volume 40 ml∕kg, respiratory rate 15-17 breaths∕min, inspiratory∕expiratory ratio 1 : 1, positive end-expiratory pressure 0, fraction of inspired oxy-gen 21％ during OLV) in group V. Methylprednisolone 2, 10 and 30 mg∕kg were intravenously injected at 20 min before mechanical ventilation in M1-3 groups, respectively, and the equal volume of normal saline was given in group V. Blood samples and lung tissues were taken at 4 h of ventilation for measurement of the lung permeability index ( LPI) and wet∕dry lung weight ratio ( W∕D ratio) , for examination of pathological changes, and for determination of apoptosis index ( AI) in lung tissues ( by TUNEL) , expression of Akt, phosphorylated Akt (p-Akt), glucose-regulated protein 78 (GRP78), CCAAT∕enhancer-binding protein homologous protein (CHOP) and caspase-12 in lung tissues (by Western blot). Injured alveoli rate (IAR) was calculated. Results Compared with group C, the W∕D ratio, LPI, IAR and AI were significantly in-creased, the expression of p-Akt was down-regulated, and the expression of GRP78, CHOP and caspase-12 was up-regulated in V and M1 groups ( P<0. 05) , and no significant change was found in the indexes mentioned above in M2 and M3 groups ( P>0. 05) . Compared with group V, the W∕D ratio, LPI, IAR and AI were significantly decreased, p-Akt expression was up-regulated, and the expression of GRP78, CHOP and caspase-12 was down-regulated in M2 and M3 groups ( P<0. 05) . Conclusion Methylprednisolone in-hibits endoplasmic reticulum stress, thus inhibiting cell apoptosis, and the mechanism is related to activa-ting PI3K∕Akt signaling pathway in rats with VILI.
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Diabetic cardiomyopathy refers to the heart disease without coronary artery disease and hypertension,diabetic patients with ventricular dysfunction.The molecular mechanism of diabetic cardiomyopathy remains unclear.Protein and lipid kinase phosphoinositol 3-kinase (PI3Ks) are thought to regulate cardiac damage in diabetes mellitus.This article reviews the role of PI3K subtypes and downstream signal transduction in the pathogenesis of diabetic cardiomyopathy,including cardiac metabolic regulation,contractility,hypertrophy,cardiomyocyte death and inflammation.
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Objective To investigate the role of PI3K/AKT in acute kidney injury (AKI) induced by abdominal sepsis in rat model. Methods The cecal ligation and puncture (CLP) was used to establish rat model of abdominal sepsis. The serum levels of creatinine (Cr) and urea nitrogen (BUN) were detected by automatic biochemical analyzer at different time points (24, 48 and 72 h) after operation. The expressions of PI3K/AKT mRNA were detected by real-time PCR. Western blot assay was used to verify the expression levels of NLRP3, ASC and Caspase-1. The serum levels of TNF-α, IL-1β and IL-18 were detected by enzyme-linked immunosorbent assay. Results The serum levels of Cr and BUN were increased significantly in CLP group compared with those of control group (P＜0.05). The expression levels of PI3K/AKT in kidney were significantly increased in rats with abdominal sepsis (P＜0.01). And the released NLRP3 inflammasome, which was activated by PI3K/AKT, was significantly increased (P＜0.01). Meanwhile, compared with the sham-operated group, the serum levels of IL-1β, TNF-α and IL-18 were increased significantly (P＜0.01). Conclusion PI3K/AKT signaling pathway plays an important role in acute kidney injury induced by abdominal sepsis, which activates the NLRP3 inflammasome, increases the release of inflammatory cytokine and aggravates the sepsis condition.
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@# Objective To investigate the protective effects of dulaglutide on Alzheimer’s disease (AD)-like neurodegenerativechangesanditsmechanismthereof. Methods Dulaglutide，anewdrugfordiabetes,wasappliedto observeandexploreAD-likeneurodegenerativechangesinducedbyPI3KinhibitorwortmannininSH-SY5Ycells.MTT assaywasusedtoobservethecellvitalityinducedbydulaglutide,wortmanninandglucagon-likepeptide(GLP-1)1receptor antagonistex9-39.WesternblotassaywasusedtodetectthelevelsofphosphorylatedTau,neurofilaments(NFs)andthe proteinsofPI3K/GSK-3βsignalingpathway.Results Dulaglutideimprovedtheimpairedvitality,increasedthelevelsof phosphorylatedPI3KandGSK-3βanddecreasedphosphorylationlevelsoftauandNFsinducedbywortmannininSHSY5Ycells.Ex9-39antagonizedtheeffectsofDulaglutide. Conclusion DulaglutideprotectsSH-SY5YcellsfromADlikeneurodegenerativechangesthroughimprovingPI3K/GSK-3βinsulinsignalingpathway.
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Objective To evaluate the role of phosphatidylinositol 3-kinase/serine-threonine kinase (PI3K/Akt) signaling pathway in carbon monoxide (CO)-induced up-regulation of the mitofusin-1 (Mfn1) expression in endotoxin-challenged rat alveolar macrophages.Methods Alveolar macrophages obtained from the rats aged 12-20 weeks were subcuhured and seeded in 96 well plates at a density of 4× 104 cells/ml.After being cultured for 24 h,the cells were divided into 4 groups (n=10 each) using a random number table:control group (group C),endotoxin group (group L),lipopolysaccharide (LPS) +CO-releasing molecule-2 (CORM-2) group (group L+C) and LPS+CORM-2+PI3K inhibitor LY294002 group (group L+C+LY).Cells were cultured normally in group C.Cells were stimulated by using LPS 10 μg/ml in L,L+C and L+C+LY groups.In group L+C,CORM-2 100 μmol was given at 1 h before stimulation with LPS.In group L+C+LY,LY294002 20 μg and CORM-2 100 μ mol were given at 1.5 and 1.0 h before stimulation with LPS,respectively.The cells were continuously incubated for 24 h after the end of treatment.The concentrations of tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) in the supernatant were determined by enzyme-linked immunosorbent assay.The expression of PI3K,phosphorylated Akt (p-Akt) and Mfn1 in cells was measured by real-time polymerase chain reaction and Western blot.Results Compared with group C,the concentration of TNF-α was significantly increased,and the IL-10 concentration was decreased in L,L+C and L+C+LY groups (P＜0.05).Compared with group L,the concentration of IL-10 was significantly increased,the TNF-α concentration was decreased,and the expression of PI3K,p-Akt and Mfn1 was up-regulated in group L+C (P＜0.05).Compared with group L+C,the concentration of IL-10 was significantly decreased,the TNF-α concentration was increased,and the expression of PI3K,p-Akt and Mfn1 was down-regulated in group L+C+LY (P＜0.05).Conclusion PI3K/Akt signaling pathway is involved in CO-induced up-regulation of Mfn1 expression in endotoxin-challenged rat alveolar macrophages.
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Objective To evaluate the relationship between endothelin-1 (ET-1) and p38 mitogenactivated protein kinase (p38 MAPK) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathways during mechanical stretch-induced enhancement of adhesion of rat pulmonary microvascular endothelial cells (PMVECs).Methods Rat PMVECs were seeded in the culture plate at a density of 0.5×105 cells/ml (2 ml/well) and divided into 5 groups (n=24 each) using a random number table:control group (group C),mechanical stretch group (group MS),mechanical stretch plus specific PI3K inhibitor LY294002 group (LY group),mechanical stretch plus specific p38 MAPK inhibitor SB203580 group (SB group),and mechanical stretch plus selective ETA receptor blocker BQ123 group (BQ group).Cells were exposed to 20％ cyclic stretch at 0.3 Hz for 4 h using a sine wave.In LY,SB and BQ groups,LY294002,SB203580 and BQ123 at the final concentration of 10 μmol/L were added,respectively,after mechanical stretch,cells were incubated for 10 min,and then extracted and purified rat polymorphonuclear neutrophil leukocytes (PMNs,5× 105 cells/well) were added and co-incubated with PMVECs for 30 min and then washed out.The concentrations of ET-1 and interleukin-6 (IL-6) in the culture medium were determined using enzyme-linked immunosorbent assay.The expression of phosphorylated p38 MAPK (p-p38 MAPK) and phosphorylated Akt (p-Akt) was detected by Western blot.Adhesion of PMNs was measured by immuno-histochemistry,and the adhesion rate was calculated.The expression of P-selectin mRNA was detected using real-time polymerase chain reaction.Results Compared with group C,the concentrations of IL-6 and ET-1 in the culture medium were significantly increased,the expression of p-p38 MAPK,p-Akt and P-selectin mRNA was up-regulated,and the adhesion rate of PMNs was increased in the other four groups (P＜0.05).Compared with group MS,the concentration of IL-6 in the culture medium was significantly decreased,the expression of p-Akt and P-selectin mRNA was down-regulated,and the adhesion rate of PMNs was decreased in LY,SB and BQ groups,the concentration of ET-1 in the culture medium was significantly decreased in group BQ,and the expression of p-p38 MAPK was significantly down-regulated in SB and BQ groups (P＜0.05).Conclusion The signaling mechanism underlying ET-1-mediated enhancement of rat PMVEC adhesion may be related to activating p38 MAPK and PI3K/Akt signaling pathways.