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.     

Effect of fucoidan on intestinal ischemia-reperfusion injury in rats

AIM:To investigate the effect and potential mechanism of fucoidan on intestinal ischemia-reperfusion (I/R) injury in rats. METHODS:Adult male Wistar rats were randomly divided into 3 groups:sham group, I/R group and Fucoidan+I/R group. Fucoidan at 160 mg/kg was intraperitoneally injected in rats of Fucoidan+I/R group 7 d prior to operation, and the equal volume of saline was intraperitoneally injected in rats of sham group and I/R group. The rats in I/R group and Fucoidan+I/R group underwent superior mesenteric artery occlusion for 1 h and then reperfusion for 2 h. Following reperfusion, the histomorphological changes of the ileum were examined by HE staining. The levels of diamine oxidase (DAO), D-lactic acid (D-LA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1β were detected in the blood samples, the levels of malondialdehyde (MDA) and glutathione (GSH), the activity of superoxide dismutase (SOD) and myeloperoxidase (MPO), and the protein levels of Bax, cleaved caspase-3 and Bcl-2 were analyzed in intestinal tissue samples. RESULTS:Compared with sham group and Fucoidan+I/R group, the serum levels of DAO, D-LA, TNF-α, IL-6 and IL-1β were significantly increased in I/R group (P<0.05), Chiu's score of intestinal tissue, MDA content, MPO activity, the levels of Bax and cleaved caspase-3 protein in the intestinal tissues were also significantly increased (P<0.05), while the tissue GSH content, SOD activity, and Bcl-2 protein levels were significantly decreased (P<0.05). CONCLUSION:Fucoidan attenuates intestinal tissue damage caused by I/R, which may be related to anti-oxidation, anti-inflammatory and anti-apoptotic effects.     

Protective effect of ischemic-preconditioning under the mild hypothermia against small intestine ischemia-reperfusion injury in rats

AIM: To investigate the protective effect of ischemic-preconditioning under the mild hypothermia against small intestine ischemia-reperfusion injury in rats and its mechanism. METHODS: Thirty-two rats were randomized into 4 groups (8 rats in each group): sham operated group (Sham), ischemia-reperfusion (I/R) group, ischemic-preconditioning (IP) group, mild hypothermia ischemic-preconditioning (MHIP) group. The wet/dry ratio, Ca²⁺-Mg²⁺-ATPase activity in intestine tissue, the malondialdehyde (MDA) content, activities of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and total antioxdase (TAX) in blood were determined. Ultrastructure, Bcl-2 and Bax expression in intestinal mucosa tissue were also observed. RESULTS: After I/R, the intestinal tissue wet/dry ratio, the content of MDA, LDH activity, the optic density of Bcl-2 and Bax proteins were significantly higher in I/R group than those in sham group (P<0.01). The activities of Ca²⁺-Mg²⁺-ATPase, SOD, TAX were significantly lower in I/R group than those in sham group (P<0.01). The intestinal tissue wet/dry ratio, the content of MDA, LDH activity and the optic density of Bax protein were significantly lower in IP group than those in I/R group (P<0.01), and also lower in MHIP group than in IP group (P<0.05). The activities of Ca²⁺-Mg²⁺-ATPase, SOD, TAX and the optic density of Bcl-2 protein were significantly higher in IP group than in I/R group (P<0.01). CONCLUSION: MHIP can protect intestine against I/R injury in rats, which may be related to enhancing oxidation-resistance of intestine, inhibiting lipid peroxidation, upregulating the expression of Bcl-2 protein and downregulating the expression of Bax protein.     

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.     

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.     

Effects of simvastatin on expression of Bcl-2 and Bax in myocardium of rats with renal ischemia-reperfusion injury

AIM: To observe the effect of simvastatin on myocardial tissue after renal ischemia-reperfusion injury and its mechanism. METHODS: A rat model of renal ischemia-reperfusion injury was prepared by clamping the bilateral renal arteries for 45 min. The rats (n=36) were randomly divided into sham operation group, renal ischemia-reperfusion (I/R) group and simvastatin group with 12 rats in each group. The content of serum creatinine (SCr), blood urea nitrogen (BUN) and myocardial tissue malondialdehyde (MDA), the myocardial activity of lactate dehydrogenase (LDH), creatine kinase (CK) and superoxide dismutase (SOD), and the myocardial protein expression of Bcl-2 and Bax were detected. RESULTS: Compared with sham operation group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in I/R group were significantly increased (P<0.05), and the activity of SOD was significantly decreased (P<0.05). Compared with I/R group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in simvastatin group were significantly decreased (P<0.05), while SOD activity was enhanced (P<0.05). The protein expression of Bcl-2 and Bax in sham operation group was less than that in I/R group (P<0.05), and the protein level of Bax in simvastatin group was significantly lower than that in I/R group (P<0.05), while the protein level of Bcl-2 was increased (P<0.05). CONCLUSION: Simvastatin has a protective effect on the myocardium of the rats with renal ischemia-reperfusion injury, and the protective mechanism may be related to the elimination of free radicals by simvastatin, increase in the protein expression of Bcl-2 and decrease in the protein expression of Bax.     

Riboflavin preconditioning alleviates hepatic ischemia/reperfusion injury in rats

AIM: To explore the protective effect of riboflavin preconditioning on hepatic ischemia/reperfusion injury in rats. METHODS: Twenty-four Sprague-Dawley rats wererandomly divided into 3 groups (n=8): sham group, ischemia/reperfusion (I/R) group and riboflavin preconditioning (R+I/R) group. The rats in sham group and I/R group received a standard chow,while the rats in R+I/R group received a chow supplemented with riboflavin. After 4 weeks, portal vein and hepatic artery supplying the middle and left hepatic lobes were clamped with a traumatic vascular clip for induction of partial hepatic ischemia in the rats in I/R group and R+I/R group. After 1 h of ischemia, 1 h of reperfusion was conducted by removal of the clip. The activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum,the activity of superoxide dismutase (SOD) and the level of malondialdehyde (MDA) in serum and liver were measured. Western blotting was employed to examine the protein expression of heme oxygenase-1(HO-1) in the liver. RESULTS: The results showed that ischemia/reperfusion injury markedly increased the activity of AST and ALT in serum, decreased the activity of SOD, and elevated the level of MDA and the activity of HO-1 in the liver as compared with sham group (P<0.01). The riboflavin pretreatment significantly decreased the activity of AST and ALT in serum, increased the activity of SOD and decreased the levels of MDA in serum and liver as compared with I/R group (P<0.01). In addition, the protein expression of HO-1 and the activity of HO-1 were elevated in R+I/R group (P<0.01). Cytoplasmic vacuolation and swelling of the hepatocytes were observed in I/R group. Treatment with riboflavin markedly alleviated the changes of liver structure. CONCLUSION: Riboflavin preconditioning has protective effect on hepatic ischemia/reperfusion injury. The mechanism may be correlated with enhancing the anti-oxidation and alleviating the reaction of lipid peroxidation.     

Apoptosis in rat hepatocytes with ischemia/reperfusion injury

AIM: To investigate the distributive rules of apoptosis index (AI) in liver with ischemia/reperfusion (I/R) injury and evaluate the factors related to the hepatocyte apoptosis. METHODS: Sixty SD rats in specific pathogen free grade were randomly divided into three groups: control group (n=18), sham operation group (n=18) and I/R group (n=24). In I/R group, liver injury was induced by blocking blood inflow in rat liver for 20 min, then reperfusion for 22 h. Rats in the control group didnt receive any management. Rats in the sham operation group only subjected sham operation. All rat blood samples and livers were obtained for determination. Blood serum ALT, AST, TBIL, TNF-α, IFN-γ, IL-4, plasma endotoxin concentration, MDA level and SOD activity in liver were detected. Hepatic histological analysis was conduced through HE staining. Apoptosis was detected by TUNEL methods. RESULTS: Focal necrosis occurred in six rats livers in I/R group, in control group and sham group no necrosis cell was found in livers. The hepatic AI of I/R group was significantly increased compared with other groups. The AI in region under hepatic amicula was higher than that in central veins region and portal area. The necrotic regions contained apoptotic cells and AI was higher than that of other regions. Hepatic AI was significantly associated with ALT, AST, TNF-α, IFN-γ and SOD/MDA. CONCLUSION: In liver with I/R injury, the apoptotic cells in the region under hepatic amicula and the focus of necrosis are significantly higher than those in other regions, apoptotic cells and necrosis cells co-exist in the same zone. Hepatic AI may be significantly associated with ALT, AST, TNF-α and SOD/MDA.     

Effects of electroacupuncture pretreatment on survival,brain injury and cognitive function in rats after limb ischemia/reperfusion

AIM：To investigate the effects of electroacupuncture (EA) pretreatment on survival, brain injury and cognitive function in rats after limb ischemia/reperfusion (LI/R). METHODS：One hundred and thirty-two healthy male SD rats weighing 255~300 g were randomly divided into 3 groups (n=44 each)：sham operation group (sham), LI/R group and LI/R plus EA pretreatment (IL/R+EA) group. The LI/R model was made by a method that the bilateral femoral arteries were occluded for 3 h with atraumatic microclips followed by 48 h of reperfusion. In sham group, sham operation was performed. The EA pretreatment was conducted twice a day for 14 d prior to the LI/R event. EA pretreatment included the following acupoints：Baihui (GV20), Zusanli (ST36) and Xuehai (SP10). The survival rate within 7 d following LI/R was calculated. The changes of cognitive function were detected 48 h after reperfusion using Morris water maze test. The cerebral water content was determined by detecting the wet and dry weight. Microglial cells were evaluated following immunolabeling of Iba1 (a marker of microglia). The protein level of cleaved caspase-3 in the hippocampus was measured by Western blotting. The neuronal apoptosis was detected using TUNEL method. Meanwhile, the changes of pathological structure in hippocampus were observed under light microscope. The activity of MPO and SOD, and the content of ROS and MDA were also investigated. RESULTS：Compared with sham group, the Iba1 positive cells, the protein level of cleaved caspase-3, the apoptotic index, and the levels of ROS/MDA and MPO activity in LI/R and LI/R+EA groups increased significantly. The normal hippocampal neurons reduced, and SOD activity decreased significantly in hippocampus. The survival rates of the rats within 7 d decreased, the latency and swimming distance increased, and the number of crossing the platform reduced. Compared with LI/R group, the above indexes in LI/R+EA group were markedly improved. CONCLUSION：EA stimulation improves the survival rate and cognitive dysfunction, and reduces brain damage in LI/R rats by preventing microglial activation and attenuating oxidative stress.     

Protective effect of recombinant SCR15-18 domain of human complement receptor type 1 on intestinal ischemia and reperfusion injury

AIM: To investigate the protective effect of recombinant SCR15-18 domain of human complement receptor type 1 (CR1-SCR-15-18) on intestinal ischemia and reperfusion in a rat model. METHODS: Sprague-Dawley rats were randomly divided into 3 groups: sham operation(SO) group, ischemia and reperfusion (I/R) group and CR1-SCR15-18 treatment group. The superior mesenteric artery of the rats was clamped for 30 min followed by 60 min of reperfusion. PBS alone or CR1-SCR15-18 protein (30 mg/kg) in PBS was intravenously administered 5 min before reperfusion. Intestinal vascular permeability, myeloperoxidase (MPO), malondialdehyde (MDA) and superoxide dismutase (SOD) were measured. The histopathological changes of intestinal mucosa were examined by HE staining and complement 3 was detected by immunohistochemical analysis. RESULTS: Compared with SO group, the vascular permeability, the activity of MPO and the content of MDA in I/R group were significantly increased, and the activity of SOD was decreased. HE staining demonstrated that I/R induced severe intestinal histological damages and the increased amount of complement 3 and its derivates were deposited in the necrosis area. Compared with I/R group, the vascular permeability, the activity of MPO and the content of MDA were decreased and the activity of SOD was significantly increased in CR1-SCR15-18 treatment group. CR1-SCR15-18 also significantly attenuated intestinal histological injury, and reduced the deposition of complement 3 and its derivates in the necrosis zone. CONCLUSION: sCR1-SCR15-18 protein exerts a protective effect against intestinal I/R injury in rats, possibly by inhibiting the activation of complement.     

Effect of intervention for mast cell function before reperfusion on intestinal ischemia-reperfusion-induced early liver injury in rats

AIM：To explore the effect of intervention for mast cell function before reperfusion on intestinal ischemia-reperfusion (IR)-induced early liver injury. METHODS：Adult SD rats (n=35) were randomized into 5 groups with 7 rats each: sham operation group (S group), IR group, cromolyn sodium treatment group (IR+C group, 25 mg/kg), ketotifen treatment group (IR+K group, 1 mg/kg), compound 48/80 treatment group (IR+CP group, 0.75 mg/kg). IR was induced by superior mesenteric artery occlusion for 75 min followed by 4 h of reperfusion. The agents were intravenously administered 5 min before reperfusion. The serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and histamine, and the liver levels of lactate dehydrogenase (LDH), tumor necrosis factor α (TNF-α), interleukin-8 (IL-8), malondialdehyde (MDA) and superoxide dismutase (SOD) were assessed. The liver histopathologic changes were also evaluated. RESULTS：IR resulted in severe liver injury as demonstrated by great increases in injury scores, concomitant significant increases in serum levels of AST, ALT and histamine, and liver levels of LDH, TNF-α, IL-8, and MDA, accompanied by reduced SOD activity (all P<0.05 vs S group). Treatment with cromolyn sodium or ketotifen markedly alleviated IR-mediated liver injury as confirmed by significant reduction of the above biomedical changes, whereas compound 48/80 further aggravated liver injury by dramatically enhancing the biomedical changes (all P<0.05 vs IR group). CONCLUSION：Inhibition of mast cell function before reperfusion may reduce early liver injury induced by intestinal ischemia reperfusion. Histamine, oxidative stress and inflammatory response may provide promising effects on it.     

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.     

Effects of electrical stimulation of vagus nerve on gut injury following intestinal ischemia-reperfusion in rats

AIM:To investigate the effects of electrical stimulation of vagus nerve on gut injury following intestinal ischemia-reperfusion in rats. METHODS:30 adult male Wistar rats subjected to bilateral cervical vagotomy were randomly divided into three groups (n=10 per group):(1) Intestinal ischemia-reperfusion group (group I/R):laparotomy and I/R induced by clamping arteria mesenterica superior for 1 h followed by reperfusion for 2 h. (2) Vagus nerve stimulation group (group VNS):laparotomy, I/R and electric stimulation with pulse train of constant amplitude 5V, pulse width 2 ms and frequency 1 Hz at the left caudal vagus ends for 20 minutes before and after occlusion. (3) Sham control group (group SC):sham operation and sham stimulation. Carotid artery was cannulated for mean arterial pressure (MAP) monitoring. A strip of small intestine was taken from distal end of ileum for light microscopic (LM) and transient electron microscopic (TEM) examination at the time of 2 h after reperfusion. Improved Chiu’s scale was used to quantitatively assay the damage degree. The levels of malondialdehyde (MDA) and TNF-α in plasma were detected. RESULTS:MAP in every group kept steady during ischemia, but decreased gradually with the prolongation in the time of reperfusion. MAP decreased more dramaticly in group I/R than that in group VNS (P<0.05). Histological changes by LM and TEM were more significant in group I/R than those in group VNS and SC. The improved Chiu’s scale in group VNS was obviously slighter than that in group I/R (P<0.05). In group I/R, the levels of MDA and TNF-α in plasma were significantly increased compared with group VNS and SC (P<0.01, P<0.05). MDA level in group VNS was significantly higher than that in group SC, but there was no significant difference in TNF-α between the two groups. CONCLUSION:Electrical stimulation of vagus nerves can lessen pathological changes of intestinal mucosa induced by I/R and improve BP during reperfusion, which may be related to reducing lipid peroxidation, and down-regulating TNF-α synthesis.     

Protective effect of all-trans retinoic acid pretreatment against rat intestinal injury induced by hepatic inflow occlusion

AIM：To investigate the effect of all-trans retinoic acid (ATRA) on the intestinal injury induced by hepatic inflow occlusion (HIO) and its mechanisms. METHODS：Thirty-two male Sprague-Dawley rats were randomly divided into four groups: sham group, HIO group, dimethyl sulfoxide (DMSO) + HIO group and ATRA (15 mg·kg-1·d-1) + HIO group. The hepatoduodenal ligament of the rats in the latter three groups was occluded (Pringle manoeuvre) by clamp for 30 min. After reperfusion for 2 h by release of the clamp, samples of distal ileum and serum were collected. Histological changes and Chiu’s scores of the ileac mucosa were evaluated under light microscope. Serum content of diamine oxidase (DAO), and ileac tissue levels of malonaldehyde (MDA) and superoxide dismutase (SOD) were analyzed by colorimetry. Serum concentrations of interleukin (IL)-1β and tumor necrosis factor (TNF)-α were evaluated by enzyme-linked immunosorbent assay method. Expression of manganese superoxide dismutase (MnSOD) in cytoplasm and nuclear factor kappa B (NF-κB) p65 in nucleus was assessed by Western blotting. RESULTS：Compared with sham group and DMSO+HIO group, ATRA significantly reduced the mucosal Chiu’s scores, the serum content of DAO and the tissue level of MDA, enhanced the serum activity of SOD and the protein expression of MnSOD, and decreased the content of NF-κB p65 in nucleus (all P<0.05). Subsequently, ATRA significantly reduced the levels of TNF-α and IL-1β in serum (P<0.05). CONCLUSION：ATRA can attenuate rat intestinal injury induced by HIO through improving the antioxidant capacity of tissue, inhibiting the activation of NF-κB and suppressing the overexpression of pro-inflammatory factors.     

Effects of Sini decoction against pulmonary injury induced by ex vivo ischemia-reperfusion in rats

AIM: To observe the effects of Sini decoction against pulmonary injury induced by ex vivo ischemia-reperfusion in rats. METHODS: The model of ischemia-reperfusion was established. Twenty-four Sprague-Dawley rats were randomly divided into Sham, I/R, and SND groups. Wet to dry lung weight ratio (W/D), mean pulmonary artery pressure (MPAP), SOD activity and MDA contents in pulmonary perfusate and tissue, NOS activity and NO contents in pulmonary tissue were detected. The pathologic changes in pulmonary tissue were also observed by light microscope. RESULTS: The morphological changes of pulmonary injury were alleviated in SND group. Wet/dry ratio, MPAP and MDA contents in pulmonary perfusate and tissue were significantly lower in SND group after ischemic/reperfusion. SOD activity in pulmonary perfusate and tissue, and NO contents in pulmonary tissue were significantly higher in SND group than those in I/R group. No significant difference in NOS activity in pulmonary tissue among three groups was observed. CONCLUSION: These results indicate that SND may have a protective effect on ischemia-reperfusion injured lung by its antioxidant activity and by adjusting NO level.     

Protective effect of non-mitogenic human acidic fibroblast growth factor from renal ischemia-reperfusion injury

AIM: To investigate the effect of non-mitogenic human acidic fibroblast growth factor (nm-haFGF) on renal ischemia-reperfusion injury in rats. METHODS: Rat renal ischemia-reperfusion (I/R) injury was produced by removing the left kidney and subsequently clamping the right renal artery for 60 min followed by reperfusion for 24 h. 5 min after reperfusion, different doses of nm-haFGF and haFGF (as positive control) were injected by lingual vein. 24 h later, the samples of blood, urine and kidney were collected and the contents of malondialdehyde (MDA),blood urea nitrogen (BUN), creatinine (Cr) and superoxide dismutase (SOD) activity were detected. Histopathological changes were also observed. RESULTS: In the serum, SOD activity of all the nm-haFGF groups and the haFGF group increased significantly while the content of MDA decreased dramatically compared with the model group; The content of BUN and Cr also decreased wherever in serum or in urine; In renal tissue, SOD activity in nm-haFGF 20 μg/kg group, 40 μg/kg group and haFGF group rose significantly compared with the model group, while MDA decreased dramatically. Histological examination showed that nm-haFGF markedly attenuates the renal edema, brush border’s defluvium and cell necrosis induced by ischemia-reperfusion. CONCLUSION: nm-haFDF could resist the renal injury induced by ischemia- reperfusion in rats.     

Ischemic postconditioning inhibits activation of nuclear factor-κB and ICAM-1 expression in lungs following intestinal ischemia reperfusion in rats

AIM: To investigate the effect of ischemic postconditioning (I-postC) on the expression of nuclear factor-κB (NF-κB) and intercellular adhesion molecule-1 (ICAM-1) in the lungs following intestinal ischemia reperfusion(II/R) in rats, and to explore the possible mechanism of I-postC in attenuating lung injury induced by II/R. METHODS: Thirty-two male Wistar rats were randomly divided into sham, II/R, intestinal ischemic postconditioning (II-postC) and limb ischemic postconditioning (LI-postC) groups. The model of intestinal I/R injury was established by clamping the super mesenteric artery for 45 min followed by 120 min of reperfusion in rats. At the end of the experiment, the changes of arterial blood gas and lung index were measured, and the morphological changes of the lung tissues were observed under light microscope. The content of malondialdehyde (MDA), the activities of superoxide dismutase (SOD) and myeloperoxidase (MPO) in the lung tissues were also detected. The contents of NF-κB p65 and ICAM-1 in lung tissue were determined by immunohistochemical staining and Western blotting. RESULTS: (1) Compared to those in II/R group, II-postC and LI-postC improved the respiratory functions of the lung, characterized by the increase in PaO₂ and decrease in PaCO₂ (P<0.05 vs II/R group). The lung index was decreased (P<0.01) and the pathologic lesion of the lung tissues was alleviated significantly by II-postC and LI-postC. (2) Both II-postC and LI-postC markedly inhibited the decrease in SOD activity, the increase in the content of MDA and the activity of MPO in the lung tissues (P<0.05 or P<0.01) induced by intestinal I/R. In addition, the over-expression of NF-κB p65 and ICAM-1 in the lung tissues was inhibited markedly by II-postC and LI-postC (P<0.05 or P<0.01 vs II/R group). CONCLUSION: I-postC attenuates lung injury induced by intestinal I/R in rats due to suppressing the activation of NF-κB and subsequent accumulation of neutrophils mediated by ICAM-1.     

Regulatory effect of miR-214-5p on myocardial injury and immune response in ischemia-reperfusion rats by targeting PAK4

AIM: To investigate the effect of microRNA-214-5p (miR-214-5p) on myocardial injury and immune response in rats with ischemia-reperfusion (I/R) by targeting p21-activated protein kinase 4 (PAK4). METHODS: The rats were divided into sham group, I/R group, Ad-Scramble group, and Ad-miR-214 group (n=9). Adenovirus was injected into 6 different sites on the anterior wall of the left ventricle of the rats. Four days later, the I/R model was constructed by suturing the left anterior descending coronary artery. The expression level of miR-214 was detected by RT-qPCR. Myocardial injury was observed by HE staining. The levels of heart damage markers (CK-MB, Mb, and cTnI) and inflammatory factors (IL-6, IL-1β and TNF-α) were measured by ELISA. The rate of cardiomyocyte apoptosis was analyzed by flow cytometry. The content of MDA and the activity of SOD were detected by commercially available kits. Target genes were predicted by genetic software and verified by dual-luciferase reporter assay. The protein levels of caspase-3, caspase-9, Bcl-2, Bax, PAK4, p-Akt and p-mTOR were determined by Western blot. RESULTS: miR-214 was down-regulated in the cardiomyocytes of I/R rats (P<0.01). Over-expression of miR-214-5p attenuated myocardial injury in the I/R rats, down-regulated the expression of CK-MB, Mb and cTnI, decreased the apoptotic rate of cardiomyocytes, up-regulated the expression of Bcl-2, down-regulated Bax, caspase-3 and caspase-9 expression, increased SOD activity, and decreased the content of MDA, IL-6, IL-1β and TNF-α (P<0.01). The binding sites of miR-214-5p and PAK4 were pre-sent in the 3’-UTR, and over-expression of miR-214-5p up-regulated the protein levels of PAK4, p-Akt and p-mTOR (P<0.01). CONCLUSION: miR-214-5p over-expression attenuates myocardial injury in I/R rats by targeting PAK4, inhibits cardiomyocyte apoptosis, oxidative stress and inflammation, and activates the PI3K/Akt/mTOR pathway.     

Protective effect of spermine on rats with acute cerebral ischemia/reperfusion injury

AIM: To study the effects and the possible mechanisms of exogenous spermine on the rats with acute transient focal cerebral ischemia/reperfusion (I/R) injury.METHODS: The rat model of focal cerebral ischemia/reperfusion was established by middle cerebral artery occlusion (2 h) and reperfusion (2 h). Healthy adult SD rats were divided into 5 groups;sham group,I/R group and spermine(4,20 and 40 mmol/L)groups.The degree of cerebral injury was evaluated by neurological deficit score, infracted volume, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. The morphological changes of the brain were observed by HE staining and electron microscopy. RESULTS: Compared with I/R group, the neurological deficit score, infracted volume and the content of MDA were decreased, the SOD activity was increased and the ultrastructural changes were improved in spermine-treated groups. CONCLUSION: Exogenous spermine has a protective effect against acute focal cerebral ischemia/reperfusion injury. The mechanisms may be related to scavenging free radical by spermine.