ABSTRACT
Objective:To evaluate the effect of dexmedetomidine on the thioredoxin-interacting protein (TXNIP)/apoptosis signal-regulated kinase 1 (ASK1) signaling pathway in a mouse model of intestinal ischemia-reperfusion (I/R).Methods:Thirty-two SPF healthy adult male C57BL/6J mice, aged 8-10 weeks, weighing 18-22 g, were divided into 4 groups ( n=8 each) using a random number table method: sham operation group (Sham group), intestinal I/R group (I/R group), TXNIP inhibitor resveratrol group (Res group) and dexmedetomidine group (Dex group). The mouse model of intestinal I/R injury was developed by clamping the superior mesenteric artery for 45 min followed by 120-min reperfusion in anesthetized animals. Resveratrol 30 mg/kg was intraperitoneally injected before developing the model in Res group, and dexmedetomidine 25 μg/kg was intraperitoneally injected at 30 min before ischemia in Dex group. Blood samples were collected by cardiac puncture at the end of 120-min reperfusion, then the mice were sacrificed, and the small intestine tissues were removed for microscopic examination and for determination of the serum diamine oxidase (DAO) concentration (by enzyme-linked immunosorbent assay) and expression of TXNIP, ASK1 and cleaved-caspase-3 in small intestinal tissues (by Western blot). The apoptosis rate of intestinal epithelial cells was calculated. The intestinal damage was assessed and scored according to Chiu. Results:Compared with group Sham, the Chiu′s score, serum DAO concentrations and apoptosis rate of intestinal epithelial cells were significantly increased, and the expression of TXNIP, ASK-1 and cleaved-caspase-3 was up-regulated in group I/R ( P<0.05). Compared with group I/R, the Chiu′s score, serum DAO concentration and apoptosis rate of intestinal epithelial cells were significantly decreased, and the expression of TXNIP, ASK-1 and cleaved-caspase-3 was down-regulated in group Res ( P<0.05). Compared with I/R group, the Chiu′s score, serum DAO concentration and apoptosis rate of intestinal epithelial cells were significantly decreased, and the expression of TXNIP, ASK-1 and cleaved-caspase-3 was down-regulated in Dex group ( P<0.05). Conclusions:The mechanism by which dexmedetomidine alleviates intestinal I/R injury may be related to inhibition of the TXNIP/ASK1 signaling pathway and reduction of cell apoptosis in mice.
ABSTRACT
Objective:To investigate the mechanism of dexmedetomidine preventing sevoflurane-indued neurotoxicity to neonatal mice and the relationship with Tau phosphorylation.Methods:Seventy-two SPF healthy newly born C57BL/6 wild-type mice of both sexes, aged 6 days, were divided into 4 groups ( n=18 each) using a random number table method: normal control group (C group), dexmedetomidine control group (D group), sevoflurane-induced neurotoxicity group (S group), and dexmedetomidine prevention group (SD group). Mice inhaled 2.1%-3.3% sevoflurane 2 h daily on postnatal days 6, 9 and 12, and dexmedetomidine 10 μg/kg was intraperitoneally injected at 30 min before anesthesia in group SD.Six mice were randomly selected after the end of injection, and the hippocampus tissues were removed for determination of the expression of phosphorylated Tau protein (AT8) and Tau46 protein at Tau-PS202 and Tau-PT205 sites by Western blot.The new object recognition test was performed on postnatal days 29-30 (the discrimination ratio of new objects was observed), and the Morris water maze test was performed from postnatal day 31 to 37 (the escape latency and the times of crossing the platform were observed). The hippocampi were harvested under anesthesia to detect the expression of postsynapatic density-95 by Western blot. Results:Compared with group C, the expression of AT8 was significantly up-regulated, the expression of PSD-95 was down-regulated, the number of crossing the platform and new object discrimination ratio were decreased ( P<0.05), and no significant change was found in Tau46 protein expression or escape latency in group S ( P>0.05). There was no significant difference in the indexes mentioned above between group D and group SD ( P>0.05). Compared with group S, the expression of AT8 was significantly down-regulated, the expression of postsynapatic density-95 was up-regulated, the number of crossing the platform and new object discrimination ratio were increased ( P<0.05), and no significant change was found in Tau46 protein expression and escape latency in group SD ( P>0.05). Conclusions:The mechanism of dexmedetomidine preventing sevoflurane-induced neurotoxicity to neonatal mice is related to the inhibition of Tau phosphorylation.
ABSTRACT
Objective:To evaluate the role of histone deacetylase (HDAC) in sodium butyrate-induced reduction of intestinal ischemia-reperfusion (I/R) injury in mice and the relationship with oxidative stress and cell apoptosis.Methods:Twenty-four SPF healthy male C57BL mice, aged 6-8 weeks, weighing 22-25 g, were divided into 4 groups ( n=6 each) according to the random number table method: sham operation group (S group), intestinal I/R group (IR group), intestinal I/R+ sodium butyrate group (IN group) and intestinal I/R+ ITSA-1+ sodium butyrate group (INI group). In IR, IN and INI groups, the superior mesenteric artery was clamped for 45 min, followed by reperfusion for 2 h to prepare the model of intestinal I/R injury, while the superior mesenteric artery was only isolated without ligation in S group.One week before preparation of the model, sodium butyrate 500 mg/kg was intragastrically administered once a day in IN group and INI group, the HDAC activator ITSA-1 0.5 mg/kg was intraperitoneally injected three times a week in INI group, and the equal volume of normal saline was given instead in the other groups.The mice were sacrificed at 2 h of reperfusion and small intestinal tissues were obtained for microscopic examination of the pathological changes which were assessed using Chiu′s score and for determination of the content of MDA (by enzyme-linked immunosorbent assay) and expression of cleaved caspase-3 (by Western blot). Results:Compared with S group, Chiu′s score was significantly increased, and the expression of cleaved caspase-3 was up-regulated in IR, IN and INI groups, the content of MDA in small intestinal tissues was significantly increased in IR and INI groups ( P<0.05). Compared with IR group, Chiu′s score was significantly decreased in IN and INI groups, and the content of MDA was significantly decreased, and the expression of cleaved caspase-3 was down-regulated in IN group ( P<0.05). Compared with IN group, Chiu′s score and content of MDA were significantly increased, and the expression of cleaved caspase-3 was up-regulated in INI group ( P<0.05). Conclusions:HDAC is involved in sodium butyrate-induced reduction of intestinal I/R injury in mice, which is related to the inhibition of oxidative stress and cell apoptosis.
ABSTRACT
Objective:To evaluate the role of histone deacetylase 6 (HDAC6) in reduction of intestinal ischemia-reperfusion (I/R) injury by sodium butyrate in mice.Methods:Twenty-four SPF healthy adult male C57BL/6 mice, aged 8-10 weeks, weighing 22-25 g, were divided into 4 groups ( n=6 each) by the random number table method: sham operation group (S group), intestinal I/R group (I/R group), intestinal I/R + sodium butyrate group (I/R+ SB group), and intestinal I/R + ITSA-1+ sodium butyrate group (I/R+ I+ SB group). The model of intestinal I/R injury was established by clipping superior mesenteric artery for 45 min followed by 120 min of reperfusion in anesthetized animals.In I/R+ I+ SB group, the HDACs activator ITSA-1 0.5 mg/kg was intraperitoneally injected at 6, 3 and 1 days before ischemia.Sodium butyrate 500 mg/kg was given by intragastric administration every day one week before ischemia in I/R+ SB group and I/R+ I+ SB group, and the equal volume of normal saline was given in S group and I/R group.At 120 min of reperfusion, the mice were sacrificed and their small intestine tissues were obtained.The levels of diamine oxidase (DAO) in serum and intestinal tissues were detected by enzyme-linked immunosorbent assay.The pathological changes of small intestinal tissues were observed with a light microscope, and intestinal damage was assessed and scored according to Chiu.The expression of microtubule-associated protein 1 light chain 3 Ⅱ (LC3 Ⅱ), P62 and HDAC6 was determined by Western blot.The contents of histone H3 (H3) and acetylated histone H3 (Ac-H3) in small intestinal tissues were determined by enzyme-linked immunosorbent assay. Results:Compared with S group, the Chiu′s score, levels of DAO in serum and small intestinal tissues were significantly increased, the expression of LC3 Ⅱ and HDAC6 was up-regulated, P62 expression was down-regulated, H3 content was increased, and AC-H3 content was decreased in I/R group ( P<0.05). Compared with I/R group, the Chiu′s score, levels of DAO in serum and small intestinal tissues were significantly decreased, the expression of LC3 Ⅱ and HDAC6 was down-regulated, P62 expression was up-regulated, H3 content was decreased, and AC-H3 content was increased in I/R+ SB group ( P<0.05). Compared with I/R+ SB group, the Chiu′s score and levels of DAO in serum and small intestinal tissues were significantly increased, the expression of LC3 Ⅱ and HDAC6 was up-regulated, P62 expression was down-regulated, H3 content was increased, and AC-H3 content was decreased in I/R+ I+ SB group ( P<0.05). Conclusions:Sodium butyrate can alleviate intestinal I/R injury by inhibition of HDAC6 activity in mice, and the mechanism may be related to inhibition of autophagy and promotion of H3 acetylation.
ABSTRACT
Objective:To evaluate the role of peroxidase proliferator-activated receptor γ (PPARγ)/nuclear factor kappa B (NF-κB) signaling pathway in sodium butyrate-induced reduction of intestinal ischemia-reperfusion (I/R) injury in mice.Methods:Thirty-two SPF-grade healthy adult male C57BL/6J mice, aged 7-9 weeks, weighing 20-25 g, were divided into 4 groups ( n=8 each) using a random number table method: sham operation group (Sham group), intestinal I/R group (IIR group), sodium butyrate group (NaB group) and PPARγ inhibitor GW9662 group (GW9662 group). The model of intestinal I/R was established by occlusion of superior mesenteric artery for 45 min followed by 2-h reperfusion in anesthetized animals.GW9662 2 mg/kg was intraperitoneally injected at 1 h before ischemia in GW9662 group, and sodium butyrate 500 mg/kg was intraperitoneally injected at 30 min before ischemia in NaB and GW9662 groups.Blood samples were obtained via cardiac puncture at 2 h of reperfusion, and the animals were then sacrificed.The intestinal tissues were removed for determination of diamine oxidase (DAO), tumor necrosis factorα (TNF-α) and interleukins 6 (IL-6) concentrations in serum (by enzyme-linked immunosorbent assay) and the expression of PPAR and NF-κB p65 (by Western blot). The damage to intestinal mucous membrane was assessed and scored according to Chiu. Results:Compared with group Sham, the Chiu′s score was significantly increased, levels of DAO, TNF-α and IL-6 in serum and intestinal tissues were increased, expression of PPARγ was down-regulated, and expression of NF-κB p65 was up-regulated in group IIR ( P<0.05). Compared with group IIR, the Chiu′s score, levels of DAO, TNF-α and IL-6 in serum and intestinal tissues were decreased, and expression of PPARγ was up-regulated in group NaB, and expression of NF-κB p65 was up-regulated in NaB and GW9662 groups ( P<0.05). Compared with group NaB, the Chiu′s score, levels of DAO, TNF-α and IL-6 in serum and intestinal tissues were increased, and expression of PPARγ was down-regulated, and expression of NF-κB p65 was up-regulated in group GW9662 ( P<0.05). Conclusion:The mechanism by which sodium butyrate reduces intestinal I/R injury may be related to activating PPARγ/NF-κB signaling pathway and inhibiting inflammatory responses in mice.
ABSTRACT
Objective:To evaluate the role of nuclear factor NF-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway in atorvastatin-induced reduction of intestinal ischemia-reperfusion (I/R) injury in mice.Methods:Twenty-four healthy male C57BL/6 mice, aged 6-8 weeks, weighing 18-22 g, were divide into 4 groups ( n=6 each) using a random number table method: sham operation group (S group), intestinal I/R group (I/R group), atorvastatin group (ATV group) and atorvastatin+ Nrf2 inhibitor ML385 group (AM group). Intestinal I/R was produced by occlusion of superior mesenteric artery for 45 min followed by reperfusion.In ATV and AM groups, atorvastatin 10 mg/kg was given by gavage for 3 consecutive days daily at 3 day before establishment of the model, while the equal volume of normal saline was given by gavage in S and I/R groups.Nrf2 inhibitor ML385 30 mg/kg was intraperitoneally injected at 1 h before establishment of the model in group AM.The mice were sacrificed at 2 h of reperfusion, and intestine tissues were obtained for examination of the pathological changes of intestinal tissues (with a light microscope) which were scored according to Chiu, for determination of wet/dry weight ratio (W/D ratio), for detection of the activity of superoxide dismutase (SOD) and content of malondialdehyde (MDA) (by xanthine oxidase method and thiobarbituric acid condensation method) and for determination of the expression of Nrf2 and HO-1 (by Western blot). Results:Compared with S group, the Chiu score, W/D ratio and MDA content were significantly increased, the activity of SOD was decreased, and the expression of Nrf2 and HO-1 was up-regulated in the other 3 groups ( P<0.05). Compared with the group I/R, the Chiu score, W/D ratio and MDA content were significantly decreased, the SOD activity was increased, and the expression of Nrf2 and HO-1 was up-regulated ( P<0.05), and the pathological changes were significantly attenuated in group ATV, and no significant change was found in the parameters mentioned above in AM group ( P>0.05). Compared with the group ATV, the Chiu score, W/D ratio and MDA content were significantly increased, the SOD activity was decreased, the expression of Nrf2 and HO-1 was decreased ( P<0.05), and the pathological changes were significantly aggravated in group AM. Conclusion:The mechanism by which atorvastatin reduces intestinal I/R injury is related to activating Nrf2/HO-1 signaling pathway in mice.
ABSTRACT
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.
ABSTRACT
Objective@#To evaluate the effect of intraperitoneally injected dexmedetomidine on abdominal adhesions in rats and the role of cholinergic anti-inflammatory pathway.@*Methods@#Forty clean-grade healthy adult male Sprague-Dawley rats, weighing 220-250 g, were divided into 4 groups (n = 10 each) using a random number table method: sham operation group (Sham group), abdominal adhesion group (AA group), dexmedetomidine group (DEX group) and dexmedetomidine plus methyllycaconitine group (DEX-M group). The rat model of abdominal adhesions was established by cecal friction method.In Sham group, abdominal cavity was only opened and then sutured.Normal saline 2 ml was injected into the abdominal cavity and tail vein in group AA.In DEX and DEX-M groups, normal saline 2 ml and α7 nicotinic acetylcholine receptor antagonist methyllycaconitine 2.4 μg/g (dissolved in 2 ml normal saline) were injected, respectively, and dexmedetomidine 10 μg/kg (dissolved in 2 ml normal saline) was intraperitoneally injected at the same time.The abdominal incision was opened under anesthesia at 7 days after establishing the model to observe the formation of abdominal adhesion, Phillips method was used for scoring, and enzyme-linked immunosorbent assay was used to determine the transforming growth factor-beta1 (TGF-β1) concentrations in ascites and tumor necrosis factor-alpha (TNF-α) concentrations in serum.The rats were then sacrificed, and the caecum tissue and its contralateral peritoneum and adhesion fibrous strips were obtained for examination of the pathological changes with a light microscope.@*Results@#Compared with group Sham, the abdominal adhesion score and serum TNF-α concentrations were significantly increased in AA and DEX-M groups, and the TGF-β1 concentration in ascites was significantly increased in AA, DEX and DEX-M groups (P<0.05). Compared with group AA, the serum TNF-α concentrations and TGF-β1 concentration in ascites were significantly decreased in group DEX-M, and the abdominal adhesion score was significantly decreased (P<0.05), and the pathological changes of caecum tissue, contralateral peritoneum and adhesion fibrous strips were significantly attenuated in group DEX.Compared with group DEX-M, the serum TNF-α concentrations were significantly increased (P<0.05), no significant change was found in TGF-β1 concentration in ascites (P>0.05), and the pathological changes of caecum tissue, contralateral peritoneum and adhesion fibrous strips were accentuated in group DEX.@*Conclusion@#Intraperitoneally injected dexmedetomidine can mitigate abdominal adhesions, and the mechanism is related to activating cholinergic anti-inflammatory pathway and reducing systemic inflammatory response in rats.
ABSTRACT
Objective To evaluate the effect of intraperitoneally injected dexmedetomidine on abdominal adhesions in rats and the role of cholinergic anti-inflammatory pathway.Methods Forty cleangrade healthy adult male Sprague-Dawley rats,weighing 220-250 g,were divided into 4 groups (n =10 each) using a random number table method:sham operation group (Sham group),abdominal adhesion group (AA group),dexmedetomidine group (DEX group) and dexmedetomidine plus methyllycaconitine group (DEX-M group).The rat model of abdominal adhesions was established by cecal friction method.In Sham group,abdominal cavity was only opened and then sutured.Normal saline 2 ml was injected into the abdominal cavity and tail vein in group AA.In DEX and DEX-M groups,normal saline 2 ml and α7 nicotinic acetylcholine receptor antagonist methyllycaconitine 2.4 μg/g (dissolved in 2 ml normal saline) were injected,respectively,and dexmedetomidine 10μg/kg (dissolved in 2 ml normal saline) was intraperitoneally injected at the same time.The abdominal incision was opened under anesthesia at 7 days after establishing the model to observe the formation of abdominal adhesion,Phillips method was used for scoring,and enzyme-linked immunosorbent assay was used to determine the transforming growth factor-beta1 (TGF-β1) concentrations in ascites and tumor necrosis factor-alpha (TNF-α) concentrations in serum.The rats were then sacrificed,and the caecum tissue and its contralateral peritoneum and adhesion fibrous strips were obtained for examination of the pathological changes with a light microscope.Results Compared with group Sham,the abdominal adhesion score and serum TNF-α concentrations were significantly increased in AA and DEX-M groups,and the TGF-β1 concentration in ascites was significantly increased in AA,DEX and DEX-M groups (P＜0.05).Compared with group AA,the serum TNF-α concentrations and TGF-β1 concentration in ascites were significantly decreased in group DEX-M,and the abdominal adhesion score was significantly decreased (P＜0.05),and the pathological changes of caecum tissue,contralateral peritoneum and adhesion fibrous strips were significantly attenuated in group DEX.Compared with group DEX-M,the serum TNF-o concentrations were significantly increased (P＜0.05),no significant change was found in TGF-1 concentration in ascites (P＞0.05),and the pathological changes of caecum tissue,contralateral peritoneum and adhesion fibrous strips were accentuated in group DEX.Conclusion Intraperitoneally injected dexmedetomidine can mitigate abdominal adhesions,and the mechanism is related to activating cholinergic anti-inflammatory pathway and reducing systemic inflammatory response in rats.
ABSTRACT
Objective To evaluate the relationship betweenα2 adrenergic receptors and expression of Nav1. 8 in dorsal root ganglion (DRG) neurons, and to illuminate the mechanism of dexmedetomidine-induced reduction of acute visceral pain in rats. Methods Thirty-two clean-grade healthy adult male Spra-gue-Dawley rats, aged 6-8 weeks, weighing 180-220 g, were divided into 4 groups ( n=8 each) using a random number table method: control group ( group C ) , acute visceral pain group ( group VP ) , dexmedetomidine group (group D), and dexmedetomidine plus atipamezole group (group DA). In VP, D and DA groups, 10-3 mmol∕L capsaicin 1. 3 ml was injected into the rectum at a dose of 10-3 mmol∕L to establish the acute visceral pain model, while the equal volume of normal saline was given instead in group C. Atipamezole 1 mg∕kg was subcutaneously injected through the back of the neck at 20 min before establishing the model in group DA. Dexmedetomidine 10μg∕kg was injected through the tail vein at 15 min before establishing the model in D and DA groups, while the equal volume of normal saline was given instead at the correspording time points in C and VP groups. The visceral pain behavior score was recorded at 1 h after establishing the model. The animals were then sacrificed, and DRGs of the lumbar segment (L3-6) were removed for determination of the number of Nav1. 8 positive DRG neurons (by immunohisto-chemistry) and expression of Nav1. 8 mRNA (by quantitative real-time polymerase chain reaction). Results Compared with group C, the visceral behavior scores and the number of Nav 1. 8 positive DRG neurons were significantly increased, and the expression of Nav 1. 8 mRNA was up-regulated in VP, D and DA groups (P<0. 05). Compared with group VP, the visceral behavior score and the number of Nav1. 8 positive DRG neurons were significantly decreased, and the expression of Nav 1. 8 mRNA was down-regulated in D and DA groups (P<0. 05). Compared with group D, the visceral behavior scores and the number of Nav1. 8 positive DRG neurons were significantly increased, and the expression of Nav1. 8 mRNA was up-regulated in group DA ( P<0. 05) . Conclusion The mechanism by which dexmedetomidine reduces acute visceral pain is related to activatingα2 adrenergic receptors and to down-regulating the expression of Nav1. 8 in DRG neu-rons of rats.
ABSTRACT
Objective To systematically compare the combined spinal-epidural block versus epidural block for labor analgesia.Methods PubMed,Embase,Cochrane Library and Web of Science were searched for randomized controlled trials involving the comparison of combined spinal-epidural block versus epidural block for labor analgesia from the date of database establishment up to September 2016.Evaluation indexes included visual analog scale scores (at 5,10 and 15 min after analgesia),onset time of analgesia,duration of analgesia,duration of the second stage of labor,cesarean section and assisted vaginal delivery,development of Apgar scores of the neonates＜7 (at 1 and 5 min after birth) and occurrence of adverse reactions.The quality of the trials was evaluated according to Cochrane Handbook 5.1.0 criteria,and meta-analysis was conducted using the Cochrane Collaboration's RevMan 5.3 software.Results Twenty studies involving 6 297 patients were included in this meta-analysis.Compared with group epidural block,visual analog scale scores were significantly decreased at 5,10 and 15 min after analgesia,the onset time of analgesia was shortened,and the incidence of pruritus and hypotension was increased in group combined spinalepidural block (P＜0.05).Conclusion Compared with epidural block,although the combined spinalepidural block has faster onset,the adverse effects are more when used for labor analgesia.
ABSTRACT
Objective To evaluate the effect of dexmedetomidine on visceral pain in rats and the role of α2 adrenergic receptors in locus coeruleus (LC).Methods Thirty-two healthy adult male SpragueDawley rats,weighing 250-300 g,were divided into 4 groups (n=8 each) using a random number table method:control group (group C),visceral pain group (group VP),dexmedetomidine group (group DEX) and α2-adrenergic receptor antagonist atipamezole group (group AP).α2-adrenergic receptor antagonist atipamezole 522 μg/kg was intramuscularly injected in group AP,and the equal volume of normal saline was given instead in C,VP and DEX groups.At 10 min after intramuscular injection,dexmedetomidine 10 μg/kg was injected via the tail vein in DEX and AP groups,and the equal volume of normal saline was given instead in C and VP groups.VP,DEX and AP groups received intraperitoneal injection of 0.9％ acetic acid 10 ml/kg to make the visceral pain model at 15 min after injection via the tail vein.The cumulative visceral pain score was recorded within 60 min after acetic acid injection.The number of c-fos positive cells in LC was detected by immunohistochemistry,and the content of norepinephrine (NA) in the spinal cord were detected by enzyme-linked immunosorbent assay at 2 h after acetic acid injection.Results Compared with group C,the cumulative visceral pain scores,the number of c-fos positive cells in LC and content of NA in the spinal cord were significantly increased in VP,DEX and AP groups (P＜0.05).Compared with group VP,the cumulative visceral pain scores,the number of c-fos positive cells in LC and content of NA in the spinal cord were significantly decreased in DEX and AP groups (P＜0.05).Compared with group DEX,the cumulative visceral pain scores,the number of c-fos positive cells in LC and content of NA in the spinal cord were significantly increased in group AP (P＜0.05).Conclusion Dexmedetomidine can alleviate visceral pain in rats,and the mechanism is partially related to activating α2 adrenergic receptors in LC.
ABSTRACT
Objective To evaluate the effect of intrathecal dexmedetomidine on expression of sub-stance P (SP) and c-fos in the spinal dorsal horns of rats with visceral pain. Methods Thirty-two clean-grade healthy adult male Sprague-Dawley rats, weighing 250-300 g, were divided into 4 groups ( n=8 each) using a random number table method: control group (C group), visceral pain group (VP group), dexmedetomidine group (D group) and dexmedetomidine plus atipamezole group (DA group). VP, D and DA groups received intraperitoneal injection of 0. 9％ acetic acid 10 ml∕kg to establish the model of visceral pain, while group C received the equal volume of normal saline instead. At 10 min before the model was es-tablished, dexmedetomidine 20 μl (1μg∕kg) and dexmedetomidine 1μg∕kg plus atipamezole 1μg∕kg (20μl) were intrathecally injected in D and DA groups, respectively, and the equal volume of normal saline 20μl was given instead in C and VP groups. Visceral pain index ( VPI) was recorded at 1 h after intraperito-neal injection, and then rats were sacrificed, and the dorsal horns of the spinal cord ( L4-6 ) were removed for determination of the expression of SP and c-fos by immunohistochemistry. Results Compared with group C, VPI was significantly increased, and the expression of SP and c-fos was up-regulated in VP, D and DA groups (P<0. 05). Compared with group VP, VPI was significantly decreased, and the expression of SP and c-fos was down-regulated in D and DA groups (P<0. 05). Compared with group D, VPI was signifi-cantly increased, and the expression of SP and c-fos was up-regulated in group DA ( P<0. 05) . Conclusion Intrathecal dexmedetomidine reduces the visceral pain through inhibiting the expression of SP and c-fos in the spinal dorsal horns, which is related to the α2-adrenergic receptor in spinal dorsal horns of rats.
ABSTRACT
Objective To evaluate the effect of oxycodone pretreatment on cell apoptosis during renal ischemia-reperfusion (I/R) in rats.Methods Thirty-six healthy male Wistar rats,weighing 180-220 g,aged 6-9 weeks,were divided into 3 groups (n=12 each) using a random number table:sham operation group (group S),renal I/R group (group I/R) and oxycodone pretreatment group (group O).The left renal pedicles were clamped with atraumatic microclips for 45 min followed by reperfusion,and the right kidney was removed immediately after onset of reperfusion to establish the model of renal I/R injury in I/R and O groups.At 10 min before ischemia,oxycodone 0.5 mg/kg was injected via the tail vein in group O,while the equal volume of normal saline was given via the tail vein instead of oxycodone in I/R and S groups.Blood samples were collected by cardiac puncture at 24 h of reperfusion for measurement of serum blood urea nitrogen (BUN) and creatinine (Cr) concentrations.The animals were then sacrificed,and the left renal specimens were obtained for examination of the pathological changes (with a light microscope) and for determination of the expression of Bcl-2,Bax and caspase-3 in renal tissues (by immunohistochemistry).Bcl-2/Bax ratio was calculated.Results Compared with group S,the serum Cr and BUN concentrations were significantly increased,the expression of Bcl-2,Bax and caspase-3 in renal tissues was up-regulated,and the Bcl-2/Bax ratio was decreased in I/R and O groups (P＜0.05).Compared with group I/R,the serum Cr and BUN concentrations were significantly decreased,the expression of Bcl-2 in renal tissues was up-regulated,the expression of Bax and caspase-3 in renal tissues was down-regulated,the Bcl-2/Bax ratio was increased (P＜0.05),and the pathological changes were significantly attenuated in group O.Conclusion The mechanism by which oxycodone pretreatment reduces renal I/R injury may be related to inhibition of cell apoptosis in rats.
ABSTRACT
Objective To evaluate the effect of sufentanil postconditioning on renal ischemia-reperfusion (I/R) injury in rats and the relationship with autophagy.Methods Thirty pathogen-free healthy adult male Wistar rats,aged 6-8 weeks,weighing 180-220 g,were divided into 3 groups (n=10 each)using a random nunber table:sham operation group (group S),group I/R and sufentanil postconditioning group (group SP).The left renal pedicle was clamped for 45 mnin with an atraumatic vascular clamp followed by reperfusion,and the right kidney was removed immediately after onset of reperfusion in anesthetized rats to establish the model of renal I/R injury in I/R and SP groups.In group S,the left renal pedicle was only isolated,and the right kidney was removed.Sufentanil 1 μg/kg was injected via the tail vein at 5 min before reperfusion in group SP,while the equal volume of normal saline was given instead in S and I/R groups.At 24 h of reperfusion,blood samples were collected by cardiac puncture for measurement of serum creatinine (Cr) and blood urea nitrogen (BUN) concentrations.The animnals were then sacrificed,and the left renal specimens were obtained for examination of pathological changes (with light microscopes) and for determination of the expression of microtubule-associated protein 1 light chain 3 (LC3) and Beclin-1 in renal tissues (by immuno-histochemistry).Results Conpared with group S,the serum Cr and BUN concentrations were significantly increased,and the expression of LC3 and Beclin-1 in renal tissues was up-regulated (P＜0.05),and the pathological changes of kidneys were aggravated in I/R and SP groups.Compared with group I/R,the serum Cr and BUN concentrations were significantly decreased,the expression of LC3 and Beclin-1 in renal tissues was down-regulated (P＜0.05),and the pathological changes of kidneys were significantly attenuated in group SP.Conclusion Sufentanil postconditioning can attenuate renal I/R injury,and the mechanism may be related to inhibition of autophagy in rats.
ABSTRACT
Objective To compare the effects of oxycodone and morphine on myocardial ischemiareperfusion (I/R) injury in rats.Methods Forty-eight SPF healthy adult male Sprague-Dawley rats,aged 8-10 weeks,weighing 250-300 g,were randomized into 4 groups (n =12 each) using a random number table:sham operation group (S group),myocardial I/R injury group (I/R group),morphine group (M group) and oxycodone group (O group).Myocardial I/R was produced by occlusion of the anterior descending branch of the left coronary artery for 30 min followed by 120 min of reperfusion.In group S,the anterior descending branch of the left coronary artery was only exposed but not ligated.In M and O groups,morphine 1.5 mg/kg and oxvcodone 0.5 mg/kg were injected,respectively,via the internal jugular vein at 5 min before ischemia.At the end of reperfusion,arterial blood samples were collected via cardiac puncture for determination of the serum creatine kinase-MB (CK-MB) and cardiac troponin Ⅰ (cTnI) concentrations.Myocardial infarct size was measured by 2,3,5-triphenyhetrazolium chloride staining.Apoptosis in cardiomyocytes was determined by TUNEL,and apoptosis index (AI) was calculated.Results Compared with S group,serum CK-MB and cTnI concentrations and AI were significantly increased,and myocardial infarct size was enlarged in I/R,M and O groups (P＜0.05).Compared with I/R group,serum CK-MB and cTnI concentrations and AI were significantly decreased,and myocardial infarct size was decreased in M and O groups (P＜0.05).Serum CK-MB and eTnI concentrations and AI were significantly lower,and myocardial infarct size was smaller in O group than in M group (P＜0.05).Conclusion Oxycodone produces better efficacy than morphine in reducing myocardial I/R injury in rats.
ABSTRACT
Objective To evaluate the effect of oxycodone pretreatment on autophagy during renal ischemia-reperfusion (I/R) in rats.Methods Thirty-six SPF healthy adult male Wistar rats,aged 6-9 weeks,weighing 180-220 g,were divided into 3 groups (n=12 each) using a random number table:sham operation group (Sham group),I/R group and oxycodone pretreatment group (Oxy group).The left renal pedicles were clamped with atraumatic microclips for 45 min followed by reperfusion to establish the model of renal I/R injury in I/R and Oxy groups.Oxycodone 0.5 mg/kg was injected via the caudal vein at 15 min before ischemia in group Oxy,and the equal volume of normal saline was given instead in I/R and Sham groups.At 24 h of reperfusion,blood samples were collected from hearts for measurement of serum creatinine (Cr) and blood urea nitrogen (BUN) concentrations.The animals were then sacrificed and left renal tissues were obtained for examination of pathological changes (with a light microscope) and for determination of Bcl-2 and Beclin-1 expression (by immunohistochemistry).Results Compared with Sham group,the concentrations of serum Cr and BUN were significantly increased,and the expression of Bcl-2 and Beclin-1 in renal tissues was up-regulated at 24 h of reperfusion in I/R and Oxy groups (P<0.05).Compared with I/R group,the concentrations of serum Cr and BUN were significantly decreased,the expression of Bcl-2 in renal tissues was up-regulated,and the expression of Beclin-1 in renal tissues was down-regulated at 24 h of reperfusion (P<0.05),and the pathological changes were significantly attenuated in Oxy group.Conclusion Oxycodone pretreatment inhibits autophagy through up-regulating the expression of Bcl-2 and down-regulating the expression of Beclin-1,thus attenuating renal I/R injury in rats.
ABSTRACT
Objective To investigate the effects of sinomenine on hind limb ischemia?reperfusion ( I∕R) injury and expression of Bcl?2 and Bax in skeletal muscle cells of rats. Methods Fifty?four healthy adult male Wistar rats, aged 6-8 weeks, weighing 180-220 g, were divided into 3 groups ( n=18 each) using a random number table: sham operation group ( group S) , group I∕R and sinomenine group ( group SIN) . The rats were subjected to 4 h of ischemia on the proximal part of the right hind limb using elastic rubber bands followed by reperfusion in I∕R and SIN groups. Sinomenine 60 mg∕kg was injected intraperito?neally at 30 min before reperfusion in group SIN, and the equal volume of normal saline was given instead of sinomenine at 30 min before reperfusion in S and I∕R groups. Immediately after onset of reperfusion and at 4 and 24 h of reperfusion, blood samples were collected from the cardiac apex to measure the concentra?tions of serum lactate dehydrogenase ( LDH) and creatine kinase ( CK) . The animals were sacrificed imme?diately after blood sampling, and the gastrocnemius specimens of the hind limb were immediately removed for determination of the wet to dry weight ratio ( W∕D ratio) and expression of Bcl?2 and Bax in gastrocnemi?us cells ( by immunohistochemistry) and for examination of the pathological changes after haematoxylin and eosin staining. The Bcl?2∕Bax ratio was calculated. Results Compared with group S, the gastrocnemius W∕D ratio and concentrations of serum LDH and CK were significantly increased, the expression of Bcl?2 was significantly down?regulated, the expression of Bax was significantly up?regulated, and the Bcl?2∕Bax ratio was significantly decreased in I∕R and SIN groups ( P<0?05) . Compared with group I∕R, the gastroc?nemius W∕D ratio and concentrations of serum LDH and CK were significantly decreased, the expression of Bcl?2 was significantly up?regulated, the expression of Bax was significantly down?regulated, and the Bcl?2∕Bax ratio was significantly increased in group SIN ( P<0?05) . The pathological changes of the gastrocne?mius were significantly attenuated in group SIN as compared with group I∕R. Conclusion Sinomenine can attenuate hind limb I∕R injury, and the mechanism may be related to maintenance of the balance between Bcl?2 and Bax and to inhibition of apoptosis in skeletal muscle cells of rats.
ABSTRACT
Objective To evaluate the effect of dexmedetomidine on lipid peroxidation during lung ischemia-reperfusion (I/R) in rats.Methods Fifty-four pathogen-free healthy male Wistar rats,weighing 250-350 g,were randomly divided into 3 groups (n=18 each) using a random number table:sham operation group (S group),I/R group,and dexmedetomidine group (Dex group).In group Dex,dexmedetomidine 5 μg/kg was injected via the caudal vein once a day for 2 consecutive days.The equal volume of normal saline was given in S and I/R groups.At 30 min after administration on 2nd day,lung I/R was produced by clamping the left hilum of lung for 45 min followed by 120 min of reperfusion in I/R and Dex groups.At 45 min of ischemia,and 60 and 120 min of reperfusion,6 rats selected from each group were sacrificed,and the left lungs were removed for examination of the pathological changes and for determination of wet/dry lung weight ratio (W/D ratio),malondialdehyde (MDA) content and superoxide dismutase (SOD) activity.Results Compared with S group,the SOD activity was significantly decreased,and the MDA content and W/D ratio were significantly increased at 60 and 120 min of reperfusion in I/R and Dex groups (P＜0.05).Compared with I/R group,the SOD activity was significantly increased,and the MDA content and W/D ratio were significantly decreased at 60 and 120 min of reperfusion in Dex group (P＜0.05).The pathological changes of lungs were significantly attenuated in Dex group as compared with I/R group.Conclusion Dexmedetomidine mitigates lung I/R injury through inhibiting lipid peroxidation in rats.
ABSTRACT
Objective To evaluate the effect of oxycodone postconditioning on myocardial ischemia-reperfusion (I/R) injury in rats.Methods Forty pathogen-free healthy adult male Sprague-Dawley rats,weighing 200-300 g,were randomly divided into 4 groups (n =10 each) using a random number table:sham operation group (group S),myocardial I/R group (group Ⅰ),oxycodone postconditioning group (group O),and selective protein kinase C inhibitor chelerythrine group (group CH).Myocardial ischemia was induced by 30 min occlusion of the left anterior descending branch of the coronary artery,followed by 120 min reperfusion.In group S,the left anterior descending branch of the coronary artery was only exposed but not ligated.In group CH,chelerythrine 5 mg/kg was injected intravenously and slowly via the jugular vein before ligation which was performed immediately after administration.In O and CH groups,oxycodone 0.5 mg/kg was injected intravenously and slowly via the jugular vein at 2 min before reperfusion.Arterial blood samples were taken at 120 min of reperfusion to detect the levels of cardiac troponin Ⅰ (cTnI) and creatine kinase-MB (CK-MB) in serum.The hearts were removed after the animals were sacrificed to measure the myocardial infarct size by TTC staining.Results Compared with group S,the levels of cTnI and CK-MB in serum and myocardial infarct size were significantly increased in Ⅰ,O and CH groups (P＜0.05).Compared with group Ⅰ,the levels of cTnI and CK-MB in serum and myocardial infarct size were significantly decreased in O and CH groups (P＜0.05).Compared with group O,the levels of cTnI and CK-MB in serum and myocardial infarct size were significantly increased in group CH (P＜0.05).Conclusion Oxycodone postconditioning can mitigate myocardial I/R injury in rats,and the mechanism is partially related to activation of protein kinase C signaling pathway.