Hydrogen sulfide reduces lipopolysaccharide-induced acute lung injury and inhibits expression of phosphorylated p38 MAPK in rats / 生理学报

To investigate the influence of hydrogen sulfide (H₂S) on p38 MAPK signaling pathway during acute lung injury (ALI) caused by lipopolysaccharide (LPS), the rats were randomly divided into six groups: control group, LPS group, LPS + NaHS group, LPS + PPG (cystathionine-γ-lyase inhibitor) group, NaHS group and PPG group. The rats were sacrificed 6 h after injection and lung tissues were obtained. The structure of lung tissues and the number of polymorphonuclear leucocyte (PMN) was observed under optical microscope; the lung myeloperoxidase (MPO) activity, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were tested; intercellular adhesion molecule-1 (ICAM-1) protein expression changes were detected by immunohistochemical staining; phosphorylated p38 MAPK (p-p38 MAPK) protein expression was detected by Western blotting. The results showed that the lung injury in LPS group was observed, at the same time the MPO activity, the content of MDA, ICAM-1 and p-p38 MAPK protein expressions, the number of PMN were all higher than those in control group (all P < 0.05). Pre-injection of NaHS alleviated the changes induced by LPS, while pre-injection of PPG aggravated those alterations (all P < 0.05). ICAM-1 and p-p38 MAPK protein expressions in lung tissue were positively correlated (r = 0.923, P < 0.01). The results suggest that H2S may reduce LPS-induced ALI through inhibiting the conjugation of p38 MAPK and reducing the expression of ICAM-1.

Role of endogenous and exogenous hydrogen sulfide in acute lung injury induced by LPS in rats / 中国应用生理学杂志

<p><b>AIM</b>To explore the role of endogenous and exogenous hydrogen sulfide (H2S) in lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats and the underlying mechanisms.</p><p><b>METHODS</b>120 Sprague-Dawley rats were randomly divided into four groups: control, LPS (instilled intratracheally to induce ALI), NaHS (H2S donor) + LPS, and propargylglycin (PPG) + LPS. Animals were sacrificed at 4 h or 8 h after agent administration. Lung weight/body weight ratio (LW/BW) was measured and calculated. Morphological changes of lung tissues were observed. H2S concentration, NO concentration (NO) and carbon monoxide (CO) level in plasma were tested. Malondialdehyde (MDA) content, CSE activity, inducible nitric oxide synthase (iNOS) activity and hemeoxygenase (HO) activity of the lung were determined. PMN and protein content in BALF were also tested. Immunohistochemisty technique was performed to examine the expression of iNOS and HO-1 protein in lung tissues. The correlation of H2S content with the above indices was analyzed.</p><p><b>RESULTS</b>Compared with control conditions, severe injuries of lung tissues and a raised LW/BW, MDA content, PMN and protein content in BALF were observed in rats treated with LPS. LPS also lead to a drop in plasma H2S concentration and lung CSE activity. The enzyme activity of iNOS and HO, the protein expression of them and plasma NO, CO level increased after LPS instillation. Administration of NaHS before LPS could attenuated the changes induced by LPS. Pre-administration of PPG exacerbated the injuries induced by LPS, increased PMN and protein content in BALF, the plasma NO level, lung iNOS activity and its protein expression, but there was no prominent variation in CO level, HO activity and HO-1 protein expression compared with those of LPS group. The H2S content was positively correlated with CSE activity, CO content and HO-1activity (r = 0.945-0.987, P < 0.01), and negatively correlated with the other indices (r = -0.994 - -0.943, P < 0.01).</p><p><b>CONCLUSION</b>Downregulation of H2S/CSE was involved in the pathogenesis of acute lung injury induced by LPS. Endogenous and exogenous H2S provided protection against the lung injuries, which might be explained by its anti-oxidative effects, attenuating inflammatory over-reaction in lung induced by PMN,the downregulation NO/iNOS system and the upregulation of CO/HO-1 system.</p>

Effects of melatonin on anti-oxidative function of lung injury induced by lipopolysaccharide in rats and ICAM-1 expression / 中国应用生理学杂志

<p><b>AIM</b>To investigate the protective effect of melatonin (MT) on lung tissues during acute lung injury (ALI) in rats and its possible mechanism.</p><p><b>METHODS</b>All rats were randomly divided into four groups: control group, lipopolysaccharide (LPS) group, dexamethasone (DEX) and MT treatment group. Myeloperoxidase (MPO) activity, superoxide dismutase (SOD) activity and malonaldehyde (MDA) content of lung tissues were detected at 3, 6 and 12 h after intratracheal instillation in each group. In addition, the expression of intercellular adhesion molecule-1 (ICAM-1) were observed through immunohistochemistry staining in lung tissues.</p><p><b>RESULTS</b>Compared with control group, SOD activity decreased significantly in LPS group (P < 0.01), but MPO activity,MDA content and the expression of ICAM-1 increased obviously (P < 0.01). The administration of MT and DEX mitigated above changes significantly (P < 0.05 or P < 0.01).</p><p><b>CONCLUSION</b>MT possessed protective effect on lung tissues during ALI through scavenging free radicals and inhibiting the expression of ICAM-1 probably.</p>

Relationship between hydrogen sulfide and myocardial damage in endotoxemic rats / 生理学报

To investigate the changes and role of hydrogen sulfide (H2S) in myocardial damage in endotoxemic rats, a rat model of endotoxemia induced by injection of lipopolysaccharide (LPS) was developed. Male Wistar rats were divided into four groups: control group, LPS group, LPS + propargylglycine (PPG, a metabolic enzyme inhibitor of H2S) group and LPS + NaHS (H2S donor) group. The mean arterial pressure (MAP) of rats within 4 h was observed, TNF-alpha and H2S contents in plasma, TNF-alpha and H2S contents, lactate dehydrogenase (LDH) and myeloperoxidase (MPO) activity in cardiac muscles were determined. The morphological structure of cardiac muscle was observed. Administration of LPS caused a sustained fall in MAP within 4 h, and significant increases in TNF-alpha and H2S contents in plasma (P<0.05). Plasmic H2S content was negatively correlated with MAP (r = -0.936, -0.913 and -0.908 at 1, 2 and 4 h, respectively, P<0.05). LPS also induced increases in TNF-alpha and H2S contents, LDH and MPO activity in cardiac muscles and myocardial damage. Treatment with PPG reduced the increases in TNF-alpha and H2S contents in plasma, TNF-alpha and H2S contents, LDH and MPO activity in cardiac muscles, ameliorated the hypotensive effect and myocardial damage caused by LPS administration (P<0.05). However, treatment with NaHS increased TNF-alpha and H2S contents in plasma, TNF-alpha and H2S contents, LDH and MPO activity in cardiac muscles, and aggravated the hypotensive action and tissue injuries caused by LPS administration (P<0.05). It is suggested that hypotension and myocardial damage in endotoxemic rats are partly induced by increase in H2S content.

The protective function of puerarin to the injury of the lung and its mechanisms during diabetes / 中国应用生理学杂志

<p><b>AIM</b>To evaluate the roles of puerarin in alleviating the STZ-induced lung injury.</p><p><b>METHODS</b>DM model was established by streptozotocin (STZ) intraperitoneal injection to study the injury mechanisms of the lung. SD rats were divided randomly into control group (C group), diabetes group (DM group), diabetes + puerarin group (DM + Pur group). The blood glucose and weight were observed and recorded before and the 20 th, 40 th, 60 thd after administration of saline, STS, STZ+ Pur. Contents of NO and malondialdehyde (MDA) and activity of superoxide dismutase (SOD) were measured in lung tissues. Light microscope (LM), transmission electron microscope (TEM) and immunohistochemical analysis were also used.</p><p><b>RESULTS</b>(1) Compared with control group, the contents of NO and MDA were increased significantly (P < 0.01), while the activity of SOD reduced (P < 0.05). Compared with DM group, treatment with puerarin inhibited the increase of NO level (P < 0.01), and MDA content began to decline from 40 days after the model was established (P < 0.01), and inhibited the decrease of SOD activity induced by DM (P < 0.01). (2) LM and TEM results showed that alveolar and capillary basement membrane became thick, the number of tiny villus decreased markedly, the quantity of osmiophilic multilamellar body reduced remarkably, hyperplasia was shown in collgen fibre. Puerarin could alleviate above injuries induced by DM. (3) Immunohistochemical staining results showed that mild brown positive stain of NT could be seen in protoplasm of lung tissues. STZ administration induced the expression of NT in the protoplasm of cells, and led to stronger positive signals of NT than that of control group. Treatment with puerarin weakened the positive stain of NT.</p><p><b>CONCLUSION</b>(1) DM induced by STZ leads to a significant and sustained increase in blood glucose and obvious lung injury, which may be associated with the overproduction of free radicals. (2) The pathway of NO/ONOO- is one of the injury mechanisms of the lung tissues cells. (3) Puerarin suppresses the expression of NT and elevates the activity of SOD. Thereby, resulting in the reduces of the production of free radicals, which may be one of the mechanisms of its anti-oxidative-injuries.</p>

Protective role of endogenous carbon monoxide to lung and kidney tissues during septic shock / 中国应用生理学杂志

<p><b>AIM</b>To study the protective role of endogenous carbon monoxide to lung and kidney tissues during septic shock and its mechanism.</p><p><b>METHODS</b>A rat model of CLP was built by using the method of CLP. The malondialdehyde (MDA) content and the activity of superoxide dematase (SOD) in blood, lung and kidney were detected by immunohistochemical technique and light microscope.</p><p><b>RESULTS</b>Pathological changes of lung and kidney in CLP + Hemin group were lighter than CLP group, inflammatory reaction and lipid peroxidation were also lighter.</p><p><b>CONCLUSION</b>Endogenous CO can protect lung and kidney from the oxidative injury. It can suppress in flammation and the oxidative injury caused by activated inflammatory cells, it is probably an important mechanism of its protective effects.</p>

The antagonism of cholecystokinin octapeptide-8 to the peroxynitrite oxidation on a diabetic cataractal rat model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cataracts is considered be formed because of an abnormal glucose metabolic pathway or oxidative stress. We explored the damaging role of ONOO- and antagonism of cholecystokinin octapeptide-8 (CCK-8) in diabetic cataractal rat lenses.</p><p><b>METHODS</b>A diabetic cataractal animal model was established by peritoneal injection of streptozotocine (STZ). Thirty-six normal SD rats were taken as control group; seventy-two were given STZ (45 mg/kg) and then divided into STZ group and CCK-8 group (peritoneal injection CCK-8). STZ induced diabetic rats were treated with CCK-8 for 60 days. Lenses were examined with slit lamp at 20, 40 and 60 days. Immunofluorescent staining and Western blot analysis were used for determining nitrotyrosine (NT, a marker for ONOO-). PT-PCR and gene array analysis were used for determining the expression of inducible nitric oxide synthetase mRNA (iNOS mRNA) in lens epithelium (LEC).</p><p><b>RESULTS</b>STZ group rats developed lens opacity by 20 days that reached a high level by 60 days after STZ injection. CCK-8 group rats delayed the cataract formation. CCK-8 group rats delayed the cataract formation. There was no distinct expression of NT and iNOS mRNA in control group. In STZ group, there were distinct expression of NT and upregulation of iNOS mRNA; however, CCK-8 group showed weak expression of NT and downregulation of iNOS mRNA.</p><p><b>CONCLUSIONS</b>NT, which may be a new form of oxidative stress, was expressed in diabetic rat LEC although CCK-8 could reverse NT damage in LEC. The results suggested that CCK-8 might be a useful therapeutic agent against diabetic cataract. The antagonizing mechanism of CCK-8 may be related to direct antagonism of ONOO- as well as its inhibition of the expression of iNOS mRNA for production of NO and therefore decrease in the formation of ONOO-.</p>

Puerarin decreases lens epithelium cell apoptosis induced partly by peroxynitrite in diabetic rats / 生理学报

The present study was designed to observe if puerarin decreases lens epithelium cell (LEC) apoptosis induced partly by peroxynitrite (ONOO(-)). One hundred and eight rats were randomly divided into control group (n=36), streptozotocin (STZ) group (n=36) and STZ + puerarin group (n=36). The rats in the control group intraperitoneally (i.p.) received 0.5 ml of saline. The rats in STZ group and STZ + puerarin group received intraperitoneal injection of STZ (45 mg/kg). Three days later, the rats in STZ + puerarin group were given puerarin (140 mg/kg per day, i.p.). On days 20, 40 and 60 of the experiment, morphologic changes of lenses were observed with slit lamp. Then the animals were sacrificed for further analysis. The amount and percentage of apoptotic LECs were determined by flow cytometry. Nitrotyrosine (NT, the foot print of ONOO(-)) was examined by immunohistochemistry. Apoptosis-related genes (iNOS, etc.) were analyzed by gene array. The results showed that in the control group, all the lenses were clear. In STZ group, gradually severe opacity of the lens was observed on days 20, 40 and 60. But in STZ + puerarin group, mild opacity of the lens was observed on day 20 and more severe on day 40, but markedly decreased on day 60. In the control group, mild apoptosis of LECs was observed. In STZ group, time-dependent increase in apoptosis of LECs was observed. In STZ + puerarin group, mild apoptosis of LECs was observed on day 20, significantly increased on day 40, but markedly decreased on day 60. There was no expression of NT in the lens in the control group, but an increased expression of NT in STZ group. In STZ + puerarin group, mild expression of NT was observed on day 20, significantly increased on day 40, but markedly decreased on day 60. There was no expression of iNOS in the lens in the control group, but continuous up-regulation of iNOS expression in STZ group. In STZ + puerarin group, mild expression of iNOS was observed on day 20, significantly increased on day 40, but markedly decreased on day 60. Except the changes of iNOS related to NO production, the other apoptosis-related genes, including BCL-2 and SOD were down-regulated, while NF-kappaB and TNFR1-FADD-caspase signal transduction way were up-regulated in STZ group. The results were opposite in STZ + puerarin group and the control group. These findings show that NT is expressed in diabetic rat lens, which proves that LEC apoptosis in diabetic lens is partly induced by ONOO(-) which may be a new oxidative damage way to form cataract. Puerarin partly decreases LEC apoptosis induced by ONOO(-) and is a potential medicine for therapy of diabetic cataract. The mechanism of puerarin dealing with diabetic cataract may be related to its direct inhibition of LEC apoptosis and antagonism of ONOO(-) in diabetic rats.

Effects and mechanisms of cholecystokinin octapeptide on hippocampal injury during endotoxic shock / 中国应用生理学杂志

<p><b>AIM</b>To study the effects and the mechanisms of cholecystokinin octapeptide(CCK-8) on hippocampal injury during endotoxic shock (ES).</p><p><b>METHODS</b>Rabbits were injected intravenously with lipopolysaccharide (LPS, 8 mg/kg) to establish ES model. Thirty-two Rabbits were divided into 4 groups at random (n = 8): control (saline, iv), LPS, CCK-8 + LPS (CCK-8 pre-administrated 30 min before LPS, iv), proglumide (Pro, nonspecific antagonist of CCK receptors) + LPS (Pro pre-administrated 30 min before LPS, iv) group. The changes of mean arterial pressure (MAP) were measured. The morphologic changes in the hippocampus were observed through light microscope (LM) and transmission electron microscope (TEM). The alterations of activities of nitric oxide synthase (NOS) and superoxide dismutase (SOD), contents of nitric oxide (NO) and malondialdehyde (MDA) in the hippocampus were assayed. Twelve Sprague-Dawley rats, grouped as that of the rabbits, were used to detect the expression of inducible NOS (iNOS) and neuronal NOS (nNOS) protein by immunohistochemistry staining.</p><p><b>RESULTS</b>LPS administration resulted insignificant reduction in MAP (P < 0.01 vs control group) and hydropic degeneration of neurons in the hippocampus. Compared with those of control group, the NOS activity, NO level and MDA content were increased significantly (P < 0.05, P < 0.01 and P < 0.05), while SOD activity was reduced (P < 0.01) in the hippocampus of ES rabbits. LPS administration induced the expression of iNOS protein in the cytoplasm of hippocampus neurons, and lead to stronger positive signals of nNOS than that of control group. CCK-8 pre-administration could alleviate the changes induced by LPS, while Pro pre-administration aggravated those alterations.</p><p><b>CONCLUSION</b>CCK-8 could protect hippocampus neurons against the injury induced by LPS during ES, which might be associated with its effects of suppressing the over production of NO and free radicals.</p>

Multiple factors contributing to lipopolysaccharide-induced reactivity changes in rabbit pulmonary artery / 生理学报

To explore the underlying mechanism(s) of pulmonary arterial hypertension in endotoxic shock, the roles of N-acetylcysteine (NAC), nitric oxide (NO) and carbon monoxide (CO) were investigated. Pulmonary arterial rings (3-mm width) were prepared from 24 rabbits. Lipopolysaccharide (LPS), after 7-hour incubation, decreased the endothelium-dependent relaxation response of the arterial ring (pre-contracted with phenylephrine) to acetylcholine (1 mumol/L), but did not affect the endothelium-independent relaxation response to sodium nitroprusside. The LPS effects were reduced by a concomitant incubation with the free radical scavenger (NAC), NO donor (L-arginine), and CO donor (hemin), respectively. On the other hand, the LPS effects were enhanced by applying heme oxygenase-1 (HO-1) inhibitor (zinc protoporphyrin) to block CO production. The response to acetylcholine changed from relaxation to contraction, however, the contractile response to phenylephrine increased significantly after pre-incubation with nitric oxide synthase (NOS) inhibitor (L-NAME) to block NO production, confirming the importance of CO and NO. These results show that LPS impairs endothelium-dependent relaxation of the pulmonary artery, which can be greatly reduced by the antioxidant, or by supplying with NO and CO. Thus, multiple factors are involved in this model of endotoxin-induced pulmonary hypertension.

Melatonin improves vascular reactivity of endotoxemia rats / 生理学报

The purpose of the present study was to investigate the effect of melatonin (MT) on the abnormal reactivity of thoracic aorta and pulmonary artery induced by lipopolysaccharide (LPS) in rats. Sprague-Dawley rats were divided into four groups randomly: (1) Vehicle group; (2) LPS group: LPS (4 mg/kg, i.p.); (3) LPS+MT group: MT (5 mg/ml, i.p.) was given 30 min before LPS and 60 min after LPS (4 mg/kg ,i.p); (4) MT group: received two doses of MT, 90 min after the first injection of MT another dose of MT was given. Six hours after LPS injection,the rats were killed and both thoracic aortic rings (TARs) and pulmonary artery rings (PARs)were prepared. The reactivity of TARs and PARs in the four subgroups was tested separately. The contraction response to phenylephrine (PE) and the endothelium-dependent relaxation response (EDRR) to ACh were observed with the isolated artery ring technique. Concentration-response curves were generated with ACh or PE (1 x 10(-8) - 1 x 10(-5) mol/L). Superoxide dismutes (SOD) activity and the content of malondialhyde (MDA) in artery tissues were detected. For TARs, LPS significantly reduced the contraction response to PE compared with the vehicle group (P<0.01) and the curve of cumulative dose responses to PE in the LPS group shifted downward. Although EDRR to ACh in the LPS group had the tendency to decrease but still showed no significant difference compared with the vehicle group (P>0.05). For PARs, EDRR to ACh was depressed significantly in the LPS group (P<0.01), while no effect on contraction response to PE in the LPS group was observed, compared with the vehicle group (P> 0.05). Compared with the LPS group, TARs in the LPS+MT group exhibited an increased contraction response to PE, but were still lower than that in the vehicle group. Similarly, EDRR to ACh of PARs in the LPS+MT group was improved significantly and there was no difference between the LPS+MT group and the vehicle group. The vascular reactivity was unaffected in MT group compared with the vehicle group in both TARs and PARs. SOD activity in the LPS +MT group increased significantly and the content of MDA decreased markedly compared with the LPS group. These results suggest that MT may improve the vascular reactivity in endotoxemia rats due to its antioxidant properties.

Changes of iNOS genes expression in liver following ischemia and reperfusion of limbs and their significance in rats / 中国应用生理学杂志

<p><b>AIM</b>To detect the changes of inducible nitric oxide synthase (iNOS) expression in liver following ischemia/reperfusion (I/R) of hindlimbs and to elucidate their significance.</p><p><b>METHODS</b>I/R was established using the occlusion of the femoral arteries for 4 h and reopening for 2-24 h in rats. The expression of iNOS mRNA, and iNOS protein and the nitrotyrosine (NT), a marker of peroxynitrite (ONOO-), in liver tissue were detected with reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical technique, respectively. The liver superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents were spectrophotometrically measured. The observation of pathologic changes of liver was made following the inhibition of iNOS by aminoguanidine (AG).</p><p><b>RESULTS</b>Compared with control groups, the relative expression level of iNOS mRNA significantly increased in I/R group. There were more iNOS positive hepatocytes and more NT positive hepatocytes in I/R group than control groups. The contents of MDA markedly increased, while the activity of SOD significantly decreased in I/R group, compared with those in the control groups. The pathologic changes of rat liver became milder in I/R group following the inhibition of iNOS by AG.</p><p><b>CONCLUSION</b>The expressions of iNOS mRNA and protein in liver are significantly upregulated, excess induction of iNOS-NO is contributed to the liver injury during the I/R of hindlimbs.</p>

The method of monitoring sleep state and respiratory rhythm in freely moving rats / 中国应用生理学杂志

<p><b>AIM</b>To devise a new method for testing the animal model of sleep apnea syndrome (SAS).</p><p><b>METHODS</b>We simultaneously monitoring the respiratory wave through a micro-pressure transducer and the electrical signals of both electrocorticogram (ECoG) and electromyogram (EMG), for detecting the sleep-wake states and the respiratory rhythm in rats. The recording data are analyzed by the manual-computer work.</p><p><b>RESULTS</b>The ECoG and EMG signals are stable and easily to distinguish. We can accurately detect the sleep-wake state and the sleep apnea events in rats by these signals.</p><p><b>CONCLUSION</b>The method is reliable to test the small animal model of SAS, and is easily to operate.</p>

Changes of HO-1 genes expression in liver following ischemia/reperfusion of limbs and their significance in rats / 中国应用生理学杂志

<p><b>AIM</b>To detect the changes of inducible heme oxygenase (HO-1) expression in liver following ischemia/reperfusion (I/R) of hindlimbs and to elucidate their significance.</p><p><b>METHODS</b>I/R was established using the occlusion of the femoral arteries for 4h and reopening for 2-24 h in rats. The expression of HO-1 mRNA and HO-1 protein in liver tissue were detected with reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical technique, respectively. The observation of pathologic changes of liver was made following the inhibition of HO-1 by zinc protoporphyrin (ZnPP).</p><p><b>RESULTS</b>Compared with control groups, the relative expression level of HO-1 mRNA significantly increased in I/R group. There were more HO-1 positive hepatocytes in I/R group than control groups. The pathologic changes of liver tissue became more severe in I/R + ZnPP group.</p><p><b>CONCLUSION</b>The expressions of HO-1 mRNA and protein in liver tissue are significantly upregulated, induction of HO-1 is involved in protection for hepatocytes during the I/R of hindlimbs.</p>

Cholecystokinin octapeptide increases free intracellular calcium of guinea pig cardiomyocytes through activation of Ca2+ channel and tyrosine kinase / 生理学报

The aim of the present study was to explore the effect of cholecystokinin octapeptide (CCK-8) on [Ca(2+)](i) and its signal transduction mechanism in isolated guinea pig cardiomyocytes. [Ca(2+)](i) was measured by laser scanning confocal microscopy in single ventricular myocytes which were dissociated by enzymatic dissociation method and loaded with Fluo 3-AM. The changes in [Ca(2+)](i) were represented by fluorescent intensity (F(i)) or relative fluorescent intensity (F(i)/F(O)%). The results obtained are as follows. (1) In the normal Tyrode's solution containing 1.0 mmol/ L Ca(2+), CCK-8 (1-10(4) pmol/L) elicited a rapid and marked increase in [Ca(2+)](i). (2) When cardiomyocytes were pretreated with the Ca(2+) chelator EGTA (3 mmol/L) and Ca(2+) channel antagonist nisoldipine (0.5 micromol/L) for 5 min, CCK-8 (10(2)pmol/L) caused a slow and small increase in [Ca(2+)](i) (p< 0.01). (3) Pretreatment with the nonselected CCK- receptor (CCK-R) antagonist proglumide (6 micromol/L) or the tyrosine kinase inhibitor genistein (1 micromol/L) for 5 min could inhibit the increase of [Ca(2+)](i) induced by CCK-8 (10(2) pmol/L) (p<0.01). The results suggest that CCK-8 increases the [Ca(2+)](i) via activating the receptor-operated Ca(2+) channel and eliciting the influx of Ca(2+) in isolated guinea pig cardiomyocytes, in which tyrosine kinase may be involved.

Change and role of heme oxygenase-1 in injured lungs following limb ischemia/reperfusion in rats / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To study the change and role of heme oxygenase-1 (HO-1) in injured lungs following limb ischemia/reperfusion in rats.</p><p><b>METHODS</b>A total of 96 healthy male Sprague-Dawley rats, weighing 250-300 g, were used in this study. Hind limb ischemia was made on 40 rats through clamping the infrarenal aorta for 2 hours with a microvascular clip, then limb reperfusion for 0, 4, 8, 16 and 24 hours (n=8 in each time point) was performed, respectively. Other 8 rats undergoing full surgical operation including isolation of the infrarenal aorta without occlusion were taken as the sham operation group. Lung tissues were obtained from the 48 animals and Northern blotting and Western blotting were employed to measure the changes of HO-1 mRNA and protein expression, respectively. Immunohistochemistry technique was used to determine the cell types responsible for HO-1 expression after limb ischemia/reperfusion. Then hind limb ischemia was made on other 12 rats through clamping the infrarenal aorta for 2 hours with a microvascular clip, among whom, 6 rats were given zinc protoporphyrin (ZnPP), an inhibitor of HO. Then limb reperfusion for 16 hours was performed on all the 12 rats. And other 12 rats underwent full surgical operation including isolation of the infrarenal aorta without occlusion, among whom, 6 rats were then given ZnPP. Then lung tissues were obtained from the 24 animals and lung injury markers, lung histology, polymorphonuclear leukocyte (PMN) count and malondialdehyde (MDA) content were detected, respectively. HO activity was determined through measuring the carboxyhemoglobin (COHb) level in artery blood with a CO-oximeter after limb ischemia/reperfusion. And the animal mortality was observed on the other 24 rats.</p><p><b>RESULTS</b>Northern blotting analysis showed that HO-1 mRNA increased significantly at 4 hours after reperfusion, peaked at 16 hours, and began to decrease at 24 hours. In contrast, no positive signal was observed in the sham and simple ischemia animals. Increased HO-1 mRNA levels were accompanied by similar increases in HO-1 protein. Lung PMNs and MDA content increased significantly at 4, 8, 16 and 24 hours after reperfusion, compared with the sham controls (P<0.001), while they decreased in rats with reperfusion for 16 hours when compared with rats with reperfusion for 4 hours (P<0.001). Immunohistochemical studies showed that HO-1 was expressed in a variety of cell types, including the airway epithelia, alveolar macrophages and vascular smooth muscular cells. The blood COHb level and animal mortality increased significantly after limb ischemia/reperfusion compared with the sham controls (P<0.001). ZnPP administrated to the ischemia/reperfusion animals led to a decrease in the COHb level and an increase in lung PMN number, MDA content and animal mortality (P<0.001 compared with ischemia/reperfusion group), and the lung injury was aggravated.</p><p><b>CONCLUSIONS</b>Limb ischemia/reperfusion up-regulates pulmonary HO-1 expression, which serves as a compensatory protective response to the ischemia/reperfusion-induced lung injury in rats.</p>

Effects of cholecystokinin-octapeptide on the tension of pulmonary artery in rabbits with endotoxic shock / 生理学报

For investigation of the regulatory mechanism of cholecystokinin-octapeptide (CCK-8) on pulmonary circulation in rabbits with endotoxic shock (ES) induced by lipopolysaccharides (LPS), mean arterial pressure (MAP) and pulmonary arterial pressure (PAP) were evaluated for 5 h in five groups of rabbits: group of LPS (8 mg/kg, i.v.)-induced ES, group of CCK-8 pretreatment (15 microg/kg, i.v.) 15 min before LPS administration (8 mg/kg, i.v.), group of proglumide pretreatment (1 mg/kg, i.v.) 15 min before LPS administration (8 mg/kg, i.v.), group of CCK (15 microg/kg, i.v.) only, and normal saline (control) group. The pulmonary arterial tension was measured with isolated vascular ring technique. The results showed that LPS-induced pulmonary arterial hypertension was abolished by CCK-8. In contrast, proglumide, a nonspecific antagonist of CCK-8 receptor, potentiated the deleterious effect of LPS. The contractile response of isolated pulmonary artery to alpha-adrenoceptor agonist phenylephrine (PE) was enhanced and the relaxation response to acetylcholine (ACh) was depressed significantly after LPS was injected, but the effect could be reversed by CCK-8. These results suggest that pulmonary circulation is improved by CCK-8 in ES, and the regulatory effects of CCK-8 may be brought about by modulating the pulmonary arterial tension.

Effect of peroxynitrite on the reactivity of rabbit pulmonary arteries in vitro / 生理学报

To investigate the effect of peroxynitrite (ONOO(-)) on the reactivity of rabbit pulmonary artery, the responses of rabbit pulmonary artery rings (PARs) pre-incubated with ONOO(-) to endothelium-dependent and receptor-dependent relaxants ACh and ADP, endothelium-dependent and receptor-independent relaxant calcium ionophore A23187, endothelium-independent relaxant sodium nitroprusside (SNP) and alpha(1)-adrenoceptor agonist phenylephrine (PE) were observed in vitro in an accumulative manner. (1) Relaxations of PARs to ACh, calcium ionophore A23187 and ADP were markedly impaired with shift of accumulative dose-response curve of each agonist to the right. Inhibition of endothelium-dependent and receptor-dependent or independent relaxation by ONOO(-) was dose-dependent. (2) ONOO(-) incubation inhibited SNP-induced relaxation in a dose-dependent manner. (3) Contractile response of PARs to PE varied with the different doses of ONOO(-). In PARs pre-incubated with 0.5 mmol/L ONOO(-), contractile response was significantly enhanced with shift of PE accumulative dose-response curve to the left, whereas in PARs pre-incubated with 1.0 mmol/L or 2.0 mmol/L ONOO(-), it was markedly reduced with right shift of PE accumulative dose-response curve. (4) Vehicle of ONOO(-) had no effect on responses to each agonist.Decomposed ONOO(-) had minimal effect on the response to PE and ADP, in contrast, relaxation of PARs to ACh, A23187 and SNP were enhanced. These results indicate that ONOO(-) may contribute to regulatory disorder of pulmonary artery reactivity.

Endogenous peroxynitrite mediates lipopolysaccharide-induced injury in cultured pulmonary artery endothelial cells / 生理学报

This study, using cultured bovine pulmonary artery endothelial cells (BPAECs), was undertaken to investigate the roles of endogenous ONOO(-) in LPS-caused injury in endothelial cells. The fluorescent intensity of nitrotyrosine (NT), a specific marker of ONOO(-) generation, in BPAECs represented the content of endogenous ONOO(-) generation. The fluorescent intensity of NT and the number of NT positive cells were detected with flow cytometry (FCM), and the percentage of NT positive cells was calculated. The results are as follows. (1) LPS (1, 5 and 10 microg/ml) caused a marked increase in fluorescent intensity of NT in a dose-dependent manner, which was significantly increased compared to the vehicle group (P<0.01).The number and percentage of NT positive cells were markedly increased (both P<0.05 vs vehicle group). Aminoguanidine (AG), a selective inhibitor of inducible nitric oxide synthase (iNOS), inhibited LPS-induced increase in fluorescent intensity of NT in BPAECs. However, the number and percentage of NT positive cells had a tendency to reduce. (2) LPS brought about an enhancement in MDA content and the activity of LDH in cultured supernatant. AG reversed the enhancement in MDA content induced by LPS (P<0.01). In contrast, AG had a marginal effect on the activity of LDH. (3) LPS induced an increase in apoptotic rate in BPAECs in a dose-dependent manner. The number of apoptotic cells markedly increased as well. Some BPAECs stained with fluorescent probe ethidium bromide showed morphological features of apoptosis with chromatin condensation and nuclear fragmentation. AG reduced the apoptotic rate and the number of apoptotic cells, both of which were still higher than those of vehicle group (P<0.05). LPS led to inhibition of mitochondrial respiration and membrane potential in an accumulation manner. In conclusion, LPS caused injury to cultured BPAECs and increased the production of ONOO(-).The cytotoxicity of LPS may be mediated by the endogenous ONOO(-).

Expression of heme oxygenase-1 induced by lipopolysaccharide in thoracic aortic and its effect on vascular reactivity / 中国应用生理学杂志

<p><b>AIM</b>To explore the effects of heme- heme oxygenase-1 (HO-1)-carbon monoxide(CO)-cyclic GMP (cGMP)on aortic vascular reactivity in endotoxemic rats and its molecular mechanism.</p><p><b>METHODS</b>By using isolated vascular ring tension detecting technique, cumulative responses of thoracic aortic rings (TARs)to phenylephrine (PE) were measured at 6 h after lipopolysaccharide administration. Effects on contractile responses to PE were measured under which the TARs were incubated with hemin (He, donor of CO), zinc-protoporphyrin-IX(ZnPP-IX, selective inhibitor of HO-1), or methylene blue (MB, inhibitor of guanylyl cyclase), respectively. The content of CO and the activity of HO-1 were measured. The protein and the gene expression of HO-1 were examined by Western blot and RT-PCR.</p><p><b>RESULTS</b>Contractile responses of TARs to cumulative doses of PE were depressed by pretreated with LPS. The hyporesponsiveness was partly reversed by incubation with ZnPP-IX and was restored to normal by incubation with MB in endotoxemic rats. Incubation with He could contribute to the vascular hyporeactivity. The content of CO, the activity and the protein and the gene expression of HO-1 were significantly increased in aorta of endotoxemic rats.</p><p><b>CONCLUSION</b>LPS could induce the HO-1 mRNA and the protein expression, the activity of HO-1 increase in aorta, lead to active the pathway of heme-HO-1-CO-cGMP, which is one of the important mechanisms of the vascular hyporeactivity in endotoxemic rats.</p>