Influence of hydrogen sulfide on ileal epithelial cell apoptosis in rats with intestinal ischemia-reperfusion injury

AIM: To investigate the influence of hydrogen sulfide (H₂S) on intestinal epithelial cell mitochondrial morphology and function and the expression of caspase-3, cleaved caspase-3, cytochrome C (Cyt C), Bcl-2 and Bax in rats with intestinal ischemia-reperfusion (I/R) injury. METHODS: Wistar rats (n=24) were randomly divided into 3 groups (8 in each group): sham group, I/R group and I/R+sodium hydrosulfide (NaHS) group. The animal model of intestinal I/R injury was established. The rats in I/R+NaHS group received NaHS (100 μmol/kg bolus +1 mg·kg^-1·h^-1 infusion) 10 min prior to the onset of reperfusion, whereas the rats in I/R group and sham group received equal volume of normal sodium. Ileum epithelial mitochondrial morphology and function were measured. Plasma H₂S was detected by sensitive sulfide electrode. The expression of Bcl-2 and Bax mRNA was studied by RT-PCR. The protein levels of caspase-3, cleaved caspase-3, cytochrome C (Cyt C), Bcl-2 and Bax were tested by Western blot.RESULTS: The area, volume density, maximum diameter, minimum diameter and equivalent diameter of mitochondria, and the expression of cleaved caspase-3, Cyt C and Bax in I/R group were significantly higher than those in I/R+NaHS and sham groups (P<0.01). The mitochondrial count, circumference, specific surface area, area density and population density, plasma H₂S, respiratory control rate (RCR), the ratio of P/O, R₃ , R₄, and the expression of Bcl-2 in I/R group were sharply lower than those in I/R+NaHS and sham groups (P<0.01). H₂S was negatively correlated with caspase-3, cleaved caspase-3, Cyt C and Bax (P<0.01), and was positively correlated with Bcl-2 (P<0.01). CONCLUSION: H₂S has a protective effect on mitochondrial morphology and function in rats with intestinal I/R injury by down-regulating cleaved caspase-3, Cyt C and Bax and up-regulating Bcl-2.     

Protective effects of glutamine pretreatment on occludin protein in rats with intestinal ischemia-reperfusion injury

AIM: To determine the effects of glutamine(Gln) pretreatment on occludin protein in the rats with intestinal ischemia-reperfusion(I/R) injury. METHODS: Male Wistar rats(n=30) were randomly divided into 3 groups(n=10):sham group, I/R group and Gln pretreatment group. The rats in Gln pretreatment group were pretreated with Gln at dose of 1 g·kg^-1·d^-1 by orogastric route for 7 d, and those in the other 2 groups were pretreated with the same volume of normal saline. Intestinal I/R was induced by 30-min occlusion of the superior mesenteric artery followed by 24 h of reperfusion. After the operation, the levels of IL-10, IL-2, TNF-α, SOD and MDA were measured. The occludin protein was determined by the methods of immunohistochemistry and Western blotting. RESULTS: The occludin protein level in I/R group was significantly lower than that in sham group and Gln group(P<0.05). The levels of MDA and TNF-α in I/R group were significantly higher than those in sham group and Gln group(P<0.05). The levels of SOD, IL-10 and IL-2 in I/R group were significantly lower than those in sham group and Gln group(P<0.05). CONCLUSION: Glutamine has a protective effect on occludin protein in intestinal ischemia-reperfusion injury. The mechanism may be rela-ted to oxidative stress response and inflammatory inhibition.     

Expression of calprotectin in rats with renal ischemia-reperfusion injury

AIM: To investigate the expression of calprotectin(CALP) in the rats with renal ischemia-reperfusion injury(IRI). METHODS: Male Sprague-Dawley rats were randomly divided into sham operation and IRI group(n=25 in each group). Blood samples and the kidneys were obtained at 6 h, 12 h, 24 h, 48 h and 72 h after reperfusion. The pathological changes of the kidneys were observed. The serum concentrations of blood urea nitrogen(BUN) and serum creatinine(SCr) were measured. The serum levels of CALP, tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) were detected by ELISA, and the expression of CALP, Toll-like receptor 4(TLR4) and NF-κB p65 in the renal tissues were determined by the methods of immunohistochemistry and Western blot. RESULTS: Different serial ischemia changes were observed in the renal tissues, mainly in the renal tubular epithelial cells and the mesenchyma, with the infiltration of inflammatory cells. The serum levels of BUN, SCr, CALP, TNF-α and IL-6 in IRI group were markedly increased as compared with sham group(P<0.05). The protein expression of CALP, TLR4 and NF-κB p65 in the renal tubular epithelial cells in IRI group was greatly enhanced in comparison with that in sham group(P<0.05). CONCLUSION: The serum concentrations of CALP, TNF-α and IL-6, and the protein expression levels of CALP, TLR4 and NF-κB p65 in the renal tissue are significantly increased in the rats with IRI, suggesting that calprotectin plays an important role in the inflammation in rats with IRI.     

Changes of aquaporin 4 expression after hepatic ischemia-reperfusion injury in rats

AIM: To study the relationship between the changes of aquaporin 4 (AQP4) expression and the liver functions in the process of hepatic ischemia-reperfusion (I/R) injury in rats. METHODS: Forty-eight Wistar rats were used to establish the animal model of hepatic I/R injury. The rats were subject to ischemia for 30 min and were randomly divided into 4 groups according to the time of reperfusion: 2 h group, 1 day group, 3 days group and 7 days group. The corresponding control animals were also set up. The serum was collected for detecting direct bilirubin (DB), indirect bilirubin (IB) and alanine transaminase (ALT). The pathological changes of the liver tissues were observed under microscope with HE staining. The protein expression of AQP4 was measured by the method of immunohistochemistry and the mRNA expression of AQP4 was detected by RT-PCR. RESULTS: Under microscope, degeneration and necrosis of the hepatic cells were observed in the liver tissues in I/R injury groups. Compared with sham operation group, the concentrations of DB, IB and ALT activity in I/R injury groups increased obviously, peaking on the first day after operation, then declining continuously and restoring to the normal levels on the 7th day after operation. The expression of AQP4 were significantly decreased in I/R injury animals in 2 h group, 1 day group and 3 days group, and reached the minimum level on the first day. The mRNA expression levels of AQP4 were also deceased in hepatic I/R injury rats in 2 h group, 1 day group and 3 days group, and reached the minimum level on the first day after operation, then increased slowly and restored to the normal levels on the 7th day after operation. CONCLUSION: Hepatic ischemia-reperfusion induces a decrease in AQP4 expression and impairs the liver functions, indicating an important role of AQP4 in the pathogenesis of liver ischemia-reperfusion injury.     

Effects of glutamine pretreatment on intestinal ischemia-reperfusion injury in rats

AIM：To determine the effects of glutamine (Gln) pretreatment on intestinal ischemia-reperfusion (I/R) injury in the rats. METHODS：Thirty male Wistar rats were randomly divided into 3 groups (n=10): sham group, I/R group and Gln pretreatment group. The rats in Gln pretreatment group were pretreated with 1 g·kg-1·d-1 Gln by orogastric route for 7 d, the rats in the other 2 groups were pretreated with normal saline. Intestinal I/R was induced by 30-min occlusion of the superior mesenteric artery followed by 24 h of reperfusion. After the operation, the plasma endotoxin, serum D-lactic acid, superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured. The intestinal mucosal injury was observed with HE staining and evaluated using Chius scoring. RESULTS：Serum D-lactic acid, endotoxin level, MDA level and Chiu's score in I/R group were significantly higher than those in sham group and Gln group (all P<0.05). Serum SOD activity was significantly lower than that in sham group and Gln group (P<0.05). CONCLUSION：Glutamine has a protective effect on the intestines during ischemia-reperfusion injury. The mechanism may be related to oxidative stress response.     

Lactulose preconditioning protects against intestinal ischemia-reperfusion injury in rats

AIM: To investigate the protective effect of lactulose preconditioning on intestinal ischemia-reperfusion (IR) injury in rats. METHODS: Thirty Sprague-Dawley rats were randomly divided into 3 groups: sham operation group, IR group and IR plus lactulose preconditioning group. Lactulose was intragastrically administered in lactulose group 7 days prior to operation, and the equal volume of saline was administered in the other 2 groups. The intestinal IR injury was induced in IR group and IR+lactulose group using bulldog clamps on superior mesenteric artery by 30 min of ischemia followed by 60 min of reperfusion. Following reperfusion, the serum samples were collected for estimating the levels of interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and IL-1β. Segments of terminal jejunum were rapidly fixed in 4% paraformaldehyde, and HE staining was applied to assess the histopathology. Apoptosis in intestinal epithelium was determined by the technique of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL). The samples of terminal jejunum were also taken for measuring malondialdehyde,superoxide dismutase and the expression of cleaved caspase-3. RESULTS: Lactulose preconditioning significantly attenuated the severity of intestinal IR injury, with inhibition of IR-induced apoptosis. Moreover, lactulose preconditioning significantly limited the release of cytokines and lipid oxidation. CONCLUSION: Lactulose preconditioning has a protective effect on intestinal ischemia reperfusion by inhibiting IR-induced apoptosis and oxidative stress.     

Effects of glucagon-like peptide-1 on myocardial ischemia-reperfusion/hypoxia-reoxygenation injury in rats

AIM: To investigate the effects of glucagon-like peptide-1 (GLP-1) on myocardial ischemia-reperfusion (IR)/hypoxia-reoxygenation (HR) injury in rats. METHODS: Sprague-Dawley rats were randomly divided into 5 groups: sham group, IR group and IR+GLP-1 (0.03 nmol/L, 0.16 nmol/L and 0.30 nmol/L) groups. IR group and IR+GLP-1 group were subject to 30 min of ischemia and 3 h of reperfusion. The myocardial infarct size, the ultrastructural changes of the myocardial tissues, the apoptosis of the cardiomyocytes, the activity of superoxide dismutase (SOD) and the concentration of malondialdehyde (MDA) were detected. Primarily cultured cardiomyocytes were divided into 5 groups at random: control group, HR group and HR+GLP-1 (1 μmol/L, 5 μmol/L and 10 μmol/L) groups. The morphology and apoptosis of the cardiomyocytes were observed. The levels of lactate dehydrogenase (LDH),MDA,SOD,reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) in different groups were detected. RESULTS: Compared with IR group, the myocardial infarct size and cardiomyocyte apoptosis were remarkably reduced, mitochondrial ultrastructures were improved, the activity of SOD was increased and the concentration of MDA was decreased in IR+GLP-1 (0.03 nmol/L, 0.16 nmol/L and 0.30 nmol/L) groups. Compared with HR group, GLP-1 (1 μmol/L, 5 μmol/L and 10 μmol/L) preconditioning significantly decreased the myocardial injury, increased SOD activity, decreased MDA concentration and ROS production, and heightened MMP in a dose-dependent manner. CONCLUSION: GLP-1 protects cardiomyocytes from IR/HR injury, which may be partially due to the effects of anti-oxidative mechanism and the function of mitochondrial protection.     

Effect of nitric oxide on apoptosis in lung injury following ischemia-reperfusion of hind limbs

AIM: To investigate the injury of lung and the role of cell apoptosis in the pathogenesis of acute lung injury following ischemia-reperfusion of hind limbs and the influence of nitric oxide (NO) to apoptosis.METHODS: Referring to our laboratory normal method,the model rats,which underwent 4 hours ischemia and 4 hours reperfusion of hind limbs were made.L-arginine (L-Arg) and N-nitro-L-arginine methyl ester (L-NAME) was administrated respectively to these rats before the experiment.Apoptosis was detected by TdT-mediated dUTP nick end labeling (TUNEL),respectively.The radioimmunoassay (RIA) was used to detect level in the expression of TNF-α.The immunohistochemistry (IHC) method was used to detect the level in the expression of Bcl-2,Bax,caspase-3 and TNF-α.The morphologic changes were observed under microscope,respectively.The results of the RIA and the IHC were analyzed quantitatively by relative computer analytical system.RESULTS: After rats’s hind limbs suffered from ischemia-reperfusion,the apoptosis in alveolar epithelial cells and pulmonary vascular endothelial cells was found.The expression of TNF-α,caspase-3 and Bax increased.Compared with IR rats,the expressions of TNF-α,caspase-3 and Bax were not obvious in the L-Arg administrated group,but the expression of Bcl-2 was obvious in that group.Compared with IR rats,the expressions of TNF-α,caspase-3 and Bax were obvious in the L-NAME administrated group,but the expression of Bcl-2 was not obvious in that group even weaker than normal ones.CONCLUSION: Apoptosis participated in acute lung injury following ischemia-reperfusion of hind limbs.The excess expression of TNF-α related with apoptosis of alveolar epithelial cells and pulmonary vascular endothelial cells.NO may reduce the occurrence of apoptosis and other lung injury through down-regulating the level in the expression of TNF-α.     

Effect of DADLE on lung injury in rats with acute global cerebral ischemia-reperfusion

AIM：To observe the effects of δ opioid receptor agonist DADLE on acute lung injury (ALI) induced by acute global cerebral ischemia-reperfusion in rats. METHODS：SD rats (n=30) were randomly divided into sham group, model (I/R) group and DADLE treatment group. Global cerebral ischemia-reperfusion model was established by a modified 2-vessel occlusion plus hypotension. DADLE (5 mg/kg) treatment was performed via the left jugular injection before reperfusion. After 120-min reperfusion, the pathological changes of the lung tissues were observed under light microscope and electronic microscope. The activity of superoxide dismutase (SOD) and malondialdehyde (MDA) level were detected. The partial pressure of arterial oxygen (PaO2) was also measured. RESULTS：In I/R group, widened alveolar septum, capillary dilatation and congestion, endovascular and perivascular cells in the lung with neutrophil infiltration, and significantly reduced type II epithelial cell surface microvilli, alveolar lumen cavity and trachea with serous exudate were observed. SOD activity decreased, but the MDA level increased. Compared with I/R group, the SOD activity increased and MDA level decreased in DADLE treatment group, with significantly reduced lung congestion, the degree of lung injury, and the infiltration of neutrophils. Compared with I/R group, the PaO2 and oxygenation index in DADLE treatment group were increased. CONCLUSION：Various degrees of pulmonary injury were observed in acute global cerebral ischemia reperfusion model. DADLE might have a protective effect on lung tissues of ALI in rats.     

Protective effects of liposomes containing L-arginine,Se and taurine on intestinal ischemia-reperfusion injury in rats

AIM and METHODS:To study the protective effects of liposomes containing L-Arg,Se and taurine on intestinal ischemia-reperfusion injury in rats. Wistar rats were divided randomly into sham operated group,ischemia-reperfusion(I/R) group,pretreatment with liposomes group and treatment with liposomes at reperfusion group. In the experiments, superior mesenteric artery was clipped for 60 min, and then unclipped. 2 hours of reperfusion later, MDA content, T-SOD and Ca²⁺-Mg²⁺-ATPase activities in intestinal tissues were detected respectively, ultrastructure and bcl-2 expression in intestinal mucosa tissue were observed.RESULTS:MDA content in liposomes-treated group was less than I/R group (P＜0.01).The activities of T-SOD and Ca²⁺-Mg²⁺-ATPase in liposomes-treated group were higher than I/R group(P＜0.01). Bcl-2 staining was negative in I/R group, and was positive in liposomes-treated group (P＜0.01).There was no difference in above indexes between pretreatment with liposomes group and treatment with liposomes at reperfusion group(P＞0.05). CONCLUSION:Liposomes containing L-arginine, Se and taurine can protect intestine against ischemia-reperfusion injury in rats,which may be related to inhibiting lipid peroxidation, stabilizing internal circumstances and inducing bcl-2 protein expression.     

Effects of icariin preconditioning on inflammatory responses in myocar-dial ischemia-reperfusion injury

AIM:To observe the effects of icariin on myocardial ischemia-reperfusion injury. METHODS:The left anterior descending coronary artery was ligated for 30 min and then loosened for 2 h to establish the rat model of myocardial ischemia-reperfusion injury. Forty-eight healthy adult male SD rats weighing 250~300 g were randomly divided into sham group, model group, low-, middle-and high-dose icariin groups, and aspirin group. The morphological changes of the myocardium were observed by HE staining. The protein expression of NF-κB p65 in the myocardial nucleus was determined by the method of immunohistochemistry. The content of tumor necrosis factor α (TNF-α) in the myocardial tissues was detected by Western blotting. The level of interleukin 1β (IL-1β) in the serum was measured by ELISA. The activity of myeloperoxidase (MPO) in the myocardial tissues was assayed by colorimetry. RESULTS:Compared with sham group, TNF-α content, IL-1β concentration, NF-κB expression and MPO activity in all other groups increased. Compared with model group, TNF-α content, IL-1β concentration, NF-κB expression and MPO activity in low-, middle- and high-dose icariin groups and aspirin group all decreased. No significant difference of the above parameters between high-dose icariin group and aspirin group was observed. CONCLUSION: Icariin preconditioning reduces inflammatory responses in the process of myocardial ischemia-reperfusion injury in a dose-dependent manner.     

Role of caspase-3 dependent hepatocyte apoptosis in liver ischemia-reperfusion injury in cirrhotic rats

AIM:To investigate whether hepatocyte apoptosis is contributed to liver ischemia-reperfusion (I/R) injury and the relationship between liver caspase-3 activity and hepatocyte apoptosis in cirrhotic rats. METHODS:Liver ischemia-reperfusion is induced by Pringle maneuver. The cirrhotic rats were randomized into two groups: Group A: simple hepatic blood inflow occlusion (HBIO); Group B: HBIO + inhibitor, before HBIO, ZVAD-fmk 15 mg/kg was injected via dorsal penis vein; Group C: healthy rat, simple HBIO. The ischemia time was 30 min in these groups. Serum aspartate aminotransferase(AST), liver caspase-3 activity, and apoptotic hepatocytes were examined in the three groups. RESULTS: After 6 h of reperfusion, the liver caspase-3 activity was markedly elevated and reached its peak, which was statistically higher than that of before I/R . The same change occurred in hepatocyte apoptosis between 6 h of reperfusion and before I/R (20.9%±4.9% vs 0.5%±0.3%, P＜0.01). As the reperfusion prolonged, the caspase-3 activity and apoptotic hepatocyte decreased gradually. The 7th-day survival rate was 62.5% in group A. The serum AST, liver caspase-3 activity and apoptotic hepatocytes were significantly higher in group A than those in group B and C, representing the most severe liver injury among the three groups. CONCLUSION:Hepatocyte apoptosis is the major form of cell death in liver ischemia-reperfusion injury in cirrhotic rats. Hepatoctye apoptosis induced by I/R is caspase-3 dependent, and inhibiting caspase-3 can alleviate liver injury. The caspase-3 dependent hepatocyte apoptosis is highly contributed to the pathological phenomenon that the ischemic sensitivity of cirrhotic liver is higher than normal liver.     

Role of HIF-1α/VEGF pathway in treatment of cerebral ischemia-reperfusion injury by hyperbaric oxygen pretreatment

AIM: To investigate the role of hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) pathway in hyperbaric oxygen (HO) pretreatment in rats with cerebral ischemia-reperfusion (IR) injury. METHODS: Healthy male SD rats (n=32) were randomly divided into control group IR group, HO-IR group and HO-IR-HIF-1α inhibitor group (HO-IR-I group). The IR model was established by middle cerebral artery occlusion. The corresponding blood vessels of the rats in control group were only exposed. The rats in HO-IR group and HO-IR-I group were treated with HO for 4 weeks before the animal modeling. The rats in HO-IR-I group received 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazol (YC-1) by intraperitoneal injection at 4 mg/kg before HO preconditioning every day. At 1 d and 7 d after modeling, the neurological assessment was evaluated.At the end of the 7 th day, after observation, the rats were sacrificed by anesthesia to measure the infarct volume of the brain tissue. The protein levels of HIF-1α, VEGF and apoptosis-related proteins Bax and Bcl-2 were determined by Western blot. The number of apoptotic cells was detected by TUNEL. RESULTS: Compared with control group, the neurological function score was decreased, while the cerebral infarction volume ratio, the protein levels of HIF-1α, VEGF, Bcl-2 and Bax, and the apoptotic cells were increased in IR group, HO-IR group and HO-IR-I group (P<0.05). Compared with IR group, the neurological function score, and the protein levels of HIF-1α,VEGF and Bcl-2 were increased, while the cerebral infarction volume ratio, the protein level of Bax and apoptotic cells were decreased in HO-IR group and HO-IR-I group (P<0.05). Compared with HO-IR group, the neurological function score, and the protein levels of HIF-1α, VEGF and Bcl-2 were decreased, while the cerebral infarction volume ratio, the protein level of Bax and apoptotic cells were increased in HO-IR-I group (P<0.05). CONCLUSION: The mechanism of HO preconditioning attenuating cerebral IR injury may be related to the regulation of apoptosis by inducing HIF-1α/VEGF signaling pathway activation.     

Establishment and evaluation of rat heart ischemia-reperfusion injury model in vivo

AIM: To establish and evaluate a rat model of heart ischemia-reperfusion injury in vivo. METHODS: Seventy-two male Sprague-Dawley rats weighing(250±50)g were randomly divided into sham operation group(sham), ischemia-reperfusion group(I/R) and normal group. The animals were anesthetized and heparinized. Myocardial ischemia-reperfusion was induced by ligating the left anterior descending coronary artery with "U-shape tube" for 35 min followed by 120 min or 240 min reperfusion in vivo. The heart infarct size was measured by triphenyltetrazolium chloride(TTC) staining. The myocardial cell apoptotic index was determined by the method of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling(TUNEL). Immunohistochemical method was used to detect the expression of Bcl-2 and Bax in rat ischemia myocardium. The blood level of MB isoenzyme of creatine kinase(CK-MB),cardiac troponin I(cTnI),nitric oxide(NO),malondialdehyde(MDA), total superoxide dismutase(T-SOD)and glutathione peroxidase(GSH-Px) were detected after reperfusion for 2 h and 4 h. RESULTS: Compared with normal group and sham group, there were obvious changes of ST-T segment and Q wave in the electrocardiogram of I/R group. The blood level of CK-MB, cTnI, NO, MDA and GSH-Px in I/R group increased(P<0.05,P<0.01) after reperfusion for 2 h and 4 h, and the blood level of T-SOD in I/R group after reperfusion for 2 h and 4 h also increased(P<0.05). The heart infarct size in I/R group was the largest as compared to other groups. Among these groups, the apoptotic index of I/R group was the highest and the Bcl-2/Bax ratio in I/R group decreased(P<0.01).CONCLUSION: The rat model of heart ischemia-reperfusion injury in vivo can be successfully established with the "U-shape tube". There are obviously changes of heart infarct size, blood level of CK-MB, cTnI, NO, MDA, T-SOD and GSH-Px, myocardial apoptotic index and Bcl-2/Bax ratio between I/R rats and control animals.     

Effect of intestinal lymphatic pathway on apoptosis of lung tissue in rats by two-hit

AIM: To observe the effects of mesenteric lymph duct ligation on apoptosis of lung tissue,correlated gene expression with apoptosis and TNF-α,IL-6 contents in rats by two-hit.METHODS: 45 Wistar rats were divided into three groups: the ligation group,the non-ligation group and sham group,and the two-hit model was established by means of hemorrhage and LPS treatments.Ligating mesenteric lymph duct was conducted in ligation group.After 24 hours,the pathological sections of lung tissue were prepared for determining the apoptosis rate by TUNEL method and expressions of Bcl-2 and Bax were observed by immunohistochemical test.The lung homogenate was also prepared for determining the contents of TNF-α and IL-6 by ELISA.RESULTS: After two-hit,the apoptosis rate,Bax expression in lung tissue and contents of TNF-α and IL-6 in serum and lung homogenate in non-ligation group were increased and Bcl-2 expression was lower than that in sham group and ligation group significantly (P<0.01,P<0.05).Apoptosis rate in ligation group was no statistics difference with sham group (P>0.05),and the expression of Bcl-2 protein was increased and Bax was lower than that of sham group (P<0.01,P<0.05).CONCLUSION: Blockage of intestinal lymphatic pathway reduces the apoptosis of lung in two-hit rats,and its mechanism might relate to reduced the levels of TNF-α and IL-6 and improved the expression of Bcl-2 protein in lung by the ligation of mesenteric lymph duct.The mesenteric lymph of two-hit might play an important role in the pathogenesis of acute lung injury (ALI).     

Advances in the mechanism of retina ischemia-reperfusion injury

Retinal ischemia-reperfusion injury (RIRI) is a common cause of visual impairment and blindness. At the cellular level, ischemic and reperfuion retinal injury consists of a self-reinforcing destructive cascade involving oxidative stress initiated by energy failure, inflammatory reaction, calcium influx, increased glutamatergic stimulation and neuronal depolarisation and apoptosis. A number of animal models and analytical techniques have been used to study the retinal ischemia-reperfusion injury, we now understand much better than ever before in the mechanism of RIRI, and an increase in the therapeutic strategies has been developed experimentally to attenuate the detrimental effects of retinal ischemia-reperfusion injury. Thus far, however, success in the laboratory has not been translated to the clinic. Given the increasing understanding of the events involved in ischemia-reperfusion neuronal injury, it is hoped that clinically effective treatments for retinal ischemia-reperfusion injury will soon be available.     

Effects of puerarin on neurological function,and synaptic morphological structure and parameter of cerebral cortex in cerebral ischemia-reperfusion rats

AIM: To investigate the protective effect of puerarin (Pue) on the neural function in a rat model of cerebral ischemia-reperfusion (IR) injury by observing synaptic morphological structural alterations and the parameter variations in brain cortex. METHODS: Male SD rats (n=69) were randomly divided into sham operation group (sham group, n=15), model group (IR group, n=18), Pue group (n=18) and nimodipine (NIM) positive control group (NIM group, n=18). The model of cerebral IR injury was established by a suture method. After ischemia for 2 h and reperfusion for 24 h, the rats in Pue group and NIM group were injected with Pue at 8 mg·kg^-1·d^-1 and NIM at 1 mg·kg^-1·d^-1, respectively, while the rats in sham group and IR group were injected with the same volume of saline. The modified neurological severity scores were evaluated at 3, 7 and 14 d, the ultrastructural changes of the synapses at the ischemic side of cerebral cortex were observed under transmission electron microscope, and the postsynaptic density was analyzed by Quantiment-520 image analysis software. RESULTS: Compared with IR group, the scores of neurological deficit were both reduced in Pue group and NIM group (P<0.05), and the difference between Pue group and NIM group was not obvious. The presynaptic and postsynaptic membranes and synaptic cleft were indistinct under electron microscope in IR group, the number of synaptic vesicles in presynaptic component was reduced, and the density of postsynaptic dense zone was decreased. The synapses were dense in Pue group and NIM group compared with IR group, the dented synapses were increased, 2 active synapses were often presented, postsynaptic density was incrassated and the synaptic cleft was clear. The curvature of synaptic interface was increased, the postsynaptic density was thickened, and the synaptic cleft was narrow in ischemic penumbra (P<0.05). The parameters of synaptic morphological structure at 7 d and 14 d were better than those at 3 d (P<0.05). CONCLUSION: The treatment with Pue promotes neural functional recovery against cerebral IR injury in the rats, which may be related to restore synaptic structure.     

Effects of ligustrazine ferulate on myocardial apoptosis and apoptosis-related protein expression in rats with myocardial ischemia-reperfusion injury

AIM:To observe the effects of ligustrazine ferulate on the apoptosis of myocardial cells in rats with myocardial ischemia-reperfusion injury, and to explore its possible mechanism. METHODS:Sixty male SD rats were randomly divided into five groups: sham-operation group, ischemia-reperfusion group, ligustrazine (4 mg/kg) group, low-dose (4 mg/kg) ligustrazine ferulate group and high-dose (8 mg/kg) ligustrazine ferulate group. The rat myocardial ischemia-reperfusion model was established by 30 min of myocardial ischemia followed by 120 min of reperfusion. Drugs were administered to the rats by jugular vein injection 10 min before reperfusion. After the reperfusion was finished, the biochemical indicators in serum and the histological indexes in myocardium were detected. RESULTS: Compared with ischemia-reperfusion group, ligustrazine ferulate lowered the serum levels of creatine kinase MB form, lactate dehydrogenase, cardiac troponin I and malondialdehyde, elevated the activity of total superoxide dismutase in serum and the expression of Bcl-2 protein in myocardium, decreased the expression of Bax protein and myocardial apoptotic index, and increased the Bcl-2/Bax ratio (all P<0.01). All the indicators in ligustrazine ferulate groups were dose-dependently superior to those in ligustrazine group (P<0.05 or P<0.01). CONCLUSION: Ligustrazine ferulate protects rats against myocardial ischemia-reperfusion injury. Its anti-apoptotic effect may be related to up-regulation of Bcl-2 and down-regulation of Bax.