Posthepatic manipulative bleeding alleviates lung injury induced by liver ischemia-reperfusion

AIM: To determine the effects of posthepatic manipulative bleeding on the lung injury induced by hepatic ischemia-reperfusion (HIR)in rat model. METHODS: Rat 35 min total hepatic ischemia model was used in this study. We treated the experimental rats by posthepatic manipulative bleeding or IH-CV manipulative bleeding at 10 min after reperfusion. RESULTS: Two percent of body weight posthepatic manipulative bleeding with blood transfusion at 10 min after reperfusion significantly decreased circulating malondialdehyde(MDA). Tissue edema, myeloperoxidase(MPO) and MDA concentrations in lung were significantly decreased 6 h after treatments. The 7 d survival rate was remarkably improved in experimental group. CONCLUSION: Two percent of body weight posthepatic manipulative bleeding with blood transfusion at 10 min after reperfusion significantly protects the rats from lung injury induced by HIR.     

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 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.     

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.     

Expression of ICAM-1 gene in the ischemia-reperfusion liver

AIM: To investigate the expression of ICAM-1 mRNA in hepatic sinusoidal cells (HSCs) during liver ischemia-reperfusion injury and its effects. METHODS: Three groups of rabbit livers experiencing ischemia for 15, 30 and 60 minutes respectively, and reperfusion for 60 minutes were conducted. The hepatic ICAM-1 mRNA expression was observed and leukocytes in hepatic sinus were counted. RESULTS: The lower expression of ICAM-1 mRNA showed in HSCs before reperfusion. Besides, leukocyte counts could no change. However, the more expression of ICAM-1 mRNA was found at the point of 60 minutes reperfusion. Furthermore, the higher expression of ICAM-1 mRNA showed in the more prolonged ischemic liver. Meanwhile, there was significant positive correlation between ICAM-1 mRNA contents and leukocyte counts. CONCLUSION: The high ICAM-1 mRNA expression induced by hepatic ischemia in HSCs increased adherence of HSCs and sequestrated more leukocytes in liver.     

Liver X receptors attenuate myocardial ischemia-reperfusion injury through modulating GLUT-4

AIM：To investigate whether liver X receptors (LXRs) attenuate myocardial ischemia-reperfusion (I/R) injury in isolated rat heart through modulating glucose transporter 4 (GLUT-4). METHODS：Isolated rat hearts were used to establish the model of ischemia-reperfusion injury using Langendorff apparatus. The hearts were divided into 7 groups: LXR agonist T0901317 (0.1, 0.5 and 10 μmol/L) pretreatment groups, ischemic preconditioning group, control group, control+DMSO group, and I/R group. The releases of lactate dehydrogenase (LDH) and creatine kinase (CK), the infarct size, the hemodynamic parameters (left ventricle developed pressure,left ventricle end-diastolic pressure, coronary flow and ±dp/dt max), the relative mRNA level of GLUT-4 and the protein content of GLUT-4 in the myocardial cell membrane were compared between these groups. RESULTS：Besides producing hemodynamic disorders, I/R increased the activities of LDH and CK, and the infarct size in model groups. Treatment with T0901317 significantly suppressed ischemia-reperfusion injury-induced increases in LDH and CK, and reduced the infarct size. T0901317 also significantly ameliorated the parameters of haemodynamics. Treatment with T0901317 significantly increased GLUT-4 expression at mRNA and protein levels in the myocardial cell membrane. CONCLUSION：Liver X receptors may attenuate myocardial ischemia-reperfusion injury in isolated rat heart by modulating the expression of GLUT-4.     

Cardioprotective effect of sevoflurane preconditioning on ROS production in rat heart with ischemia-reperfusion

AIM: To investigate the effects of sevoflurane preconditioning on the production of reactive oxygen species (ROS) and nitric oxide (NO), the activity of superoxide dismutase(SOD), glutathione peroxide(GPx) and catalase(CAT) in myocardial ischemia-reperfusion injury(IRI). METHODS: Sixty rats were randomly allocated to 8 groups. Following 2% sevoflurane preconditioning for 30 min, the left anterior descending artery was ligated for 30 min and then reperfused for 120 min in vivo. The infarction size of the hearts was measured with the staining of 2,3,5-triphenyltetrazoliumchloride. The myocardial apoptotic index was measured by the method of TUNEL. The ROS fluorescent probe dihydroethidium was used for the measurement of ROS. The myocardium was homogenized for the measurement of NO, SOD, GPx and CAT. To evaluate the effects of ROS and NO on the cardioprotection of sevoflurane preconditioning, ROS scavenger N-(2-mercaptopropionyl) glycine (2-MPG) or NOS inhibitor N^ω-nitro-L-arginine methyl ester (L-NAME) were employed to block their actions. RESULTS: Compared with control group, the production of ROS was induced by sevoflurane preconditioning before ischemia-reperfusion injury (12.0±0.8 vs 2.6±0.5, P<0.05) and decreased after ischemia-reperfusion injury (16.2 ±0.9 vs 24.9±1.3, P<0.05). 2-MPG decreased the elevation of ROS caused by sevoflurane preconditioning before ischemia-reperfusion injury (5.1±0.7 vs 12.0±0.8, P<0.05). No difference of ROS production between treating with 2-MPG+Sevo+IRI and with IRI (24.9±1.4 vs 24.9±1.3, P>0.05) was observed. Compared with control group, sevoflurane preconditioning also induced the generation of NO (34.5±3.2 vs 15.9±1.4, P<0.05) and the activity of SOD(1.5±0.5 vs 0.6±0.2, P<0.05), GPx(22.8±2.5 vs 12.7±2.2, P<0.05) and CAT(15.5±1.8 vs 11.2±1.4, P<0.05). 2-MPG blocked the increase in NO production and inhibited the activity of SOD,GPx,CAT. L-NAME also attenuated the activity of SOD,GPx,CAT. CONCLUSION: Sevoflurane preconditioning protects the rat heart against ischemia-reperfusion injury by reducing the infarction size and apoptosis. Production of ROS at sub-injury dose induced by sevoflurane preconditioning stimulates the myocardium to create SOD,GPx,CAT and NO, thus inhibiting the further formation of ROS and protecting the heart under the condition of ischemia-reperfusion.     

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 spermine on myocardial ischemia/ reperfusion injury in rats

AIM: To observe the effect of exogenous spermine (low concentration) on myocardial ischemia/reperfusion injury in rats.METHODS: 40 Wistar rats were randomly divided into 4 groups: sham- operation group (Sham), ischemic reperfusion group (I/R), spermine group (Sp) and natural saline group (NS). The model of ischemic/reperfusion injury was established by ligating rat coronary artery. In Sp group, spermine (0.5 mmol/L, 2 mL/kg) was injected slowly into rat vein. During the process, we recorded the electrocardiogram and the LV functional parameters, assayed the levels of SOD, LDH, NO and MDA in serum, and examined the ultrastructure of the myocardium. RESULTS: In I/R group, the incidence of arrhythmia was 90%, myocardial ultrastructure was injured seriously, values of LVSP and ±dp/dtmax decreased, levels of LDH, NO and MDA increased while SOD activity decreased (P<0.05 or P<0.01, compared with Sham group). Compared with I/R and NS group, all those indexes in Sp group changed significantly (P<0.05 or P<0.01). CONCLUSION: Exogenous spermine alleviates myocardial ischemia/ reperfusion injury in rats. The mechanism may be related to its antioxidant effect and relieving the injury caused by oxygen free radical.     

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.     

Protective effect of hydrogen sulfide on hypoxia-induced injury of rat cortical neurons

AIM:To explore the role of hydrogen sulfide (H 2S) in cortial neuronal injury induced by hypoxia.METHODS:The SD rat cortical neurons were cultured in hypoxic conditions (2% O 2, 5% CO 2 and 93% N 2 at 37 °C) to establish the hypoxic model. Sodium hydrosulfide (NaHS) was used as the donor of H 2S and neuronal viability was detected by CCK-8 assay. Neuronal content of reactive oxygen species (ROS) was determined by DCFH-DA method, and mitochondrial membrane potential (MMP) was detected using Rh123 staining. Lactate dehydrogenase (LDH) release rate was measured by a commercial kit to reflect the degree of neuronal injury. RESULTS:Hypoxic treatment increased ROS content and the release rate of LDH in the neurons. However, NaHS pretreatment significantly inhibited the hypoxia-induced increases in ROS content and LDH release. Hypoxia decreased MMP and cell viability. Pretreatment with NaHS and N-acetyl-L-cysteine (NAC), a ROS scavenger, significantly inhibited the decreases in MMP and viability of the neurons. CONCLUSION:Hypoxia induces ROS generation in the neurons, thereby decreases MMP and neuronal viability. H 2S significantly attenuates hypoxia-induced neuronal injury by its antioxygenation.     

Shenfu injection prevents kidney from acute ischemia-reperfusion injury in rabbits

AIM:To further investigate preventive effects of Shenfu(SF) injection, a Chinese herb drug, on acute renal ischemic reperfusion injury (IRI).METHODS:After SF or normal saline was administered intravenously one t ime a day for four days,the renal ichemia-reperfusion(I-R)model was established by occlusion of right renal artery and vein for an hour and reperfusion for three hours after left nephroectomy.The activity of superoxide dismutase (SOD),content of malondialdehyde(MDA)in serum and renal tissue,and content of nitric oxide(NO),concentrat ions of Na⁺ and Ca²⁺ ,numbers of WBC adhesion in renal t issue were detected and light and electronic microscopy were used or the detection of the renal histological changes. RESULTS:SF lowered significantly MDA content in either renal tissues or serum , concentration of Na⁺, the number of WBC adhesion, and scores of tubules in renal tissue after renal I-R, and the SOD activity in renal tissues and serum and NO content in renal tissue were obviously increased by SF.In addition, renal histomorphological damage in either light or electronic microscope were lightened by SF. But Ca²⁺concentration in renal tissue appeared to be only mildly affected. CONCLUSION:The mechanisms that SF protects renal structure and function against acute renal IRI may be involved in increasing SOD activity, scavenging directly oxygen free redicals(OFR), raising NO content, inhibiting WBC adhesion and recruiment, preventing Na⁺ influx to form Na⁺ overload.     

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 sulfur dioxide in acute lung injury induced by ischemia-reperfusion of hind limbs in rats

AIM：To explore the role of endogenous and exogenous sulfur dioxide(SO2) in acute lung injury(ALI) induced by ischemia-reperfusion(IR) of limbs in rats. METHODS：The rat model of ALI was induced by ischemia and reperfusion of the hind limbs using a tourniquet. The rats(n=96) were randomly divided into 6 groups: sham, IR, sham+SO2, sham+hydroxamate(HDX), IR+SO2 and IR+HDX. The morphological changes of the lung tissues were observed under light microscope. Meanwhile, polymorphonuclear neutrophils(PMN) in alveolar septum, lung coefficient, lung levels of malondialdehyde(MDA) and intercellular adhesion molecule(ICAM)-1, serum tumor necrosis factor(TNF)-α and interleukin(IL)-1, the content of SO2 and the activity of aspartate aminotransferase(AST) in the lung tissues, and 24 h survival rate of the rats were measured. RESULTS：IR of the rat limbs resulted in the damage of the lung tissues, and the increases in PMN in alveolar septum, lung coefficient, the lung levels of MDA and ICAM-1 and the serum levels of TNF-α and IL-1 were also observed with the reductions of SO2 content and AST activity. Pretreatment with SO2 donor Na2SO3/NaHSO3 alleviated the changes of the indicators above. HDX, an inhibitor of SO2-producing enzymes, aggravated the changes above. CONCLUSION：Down-regulation of AST/SO2 pathway is involved in the pathogenesis of limb IR-induced ALI. Administration of exogenous SO2 might attenuate lung injury through anti-inflammation and anti-oxidation.     

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.     

siRNA targeting fas protects donor liver against cold preservation and ischemic reperfusion injury in rat liver transplantation

AIM:To investigate the silencing effect of fas siRNA to alleviate ischemic-reperfusion (I/R) injury in liver transplantation. METHODS:Three pairs of 21-nt synthesized fas siRNAs were transfected into BRL cells respectively for evaluation of silence efficacy, and the most effective fas siRNA was chosen in vivo for experiment. In cold preservation experiment, siRNA was transfected in vivo by hydrodynamics method. After 48 h, livers of fas siRNA group and control group were harvested and cold preserved, and cell apoptosis and fas expression was evaluated at 2, 4 and 6 h. Orthotopic liver transplantation was performed in fas siRNA group and blank control group. At 1, 3, 6, 12 and 24 h after transplantation, blood and liver samples were collected for evaluation of serum ALT levels, Fas protein and mRNA expression, and apoptosis by TUNEL staining. RESULTS:fas siRNA2, which began at nt 315, inhibited fas gene expression much more than other siRNAs. As to cold preservation, apoptosis index (AI) and fas expression in fas siRNA group was lower than that in control group at each checked point (P<0.01). At 1, 3, 6, 12, and 24 h after blood reperfusion of liver transplantation, the serum ALT level in fas siRNA group was much less than that in control group. The cell apoptosis in fas siRNA group was substantially decreased, and the expressions of fas mRNA and protein were dramatically reduced. CONCLUSION:fas-mediated apoptosis plays an important role in I/R injury of rat liver transplantation. Silencing fas by siRNA holds therapeutic promise to limit I/R injury.     

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.     

Effects of EDRV and DIDS on reactive oxygen species levels in acute ischemia-reperfusion injured myocardium

AIM: To investigate the effects of chloride channel inhibitor 4,4- diisothiocyanostilbene-2,2- disulfonic acid (DIDS) and free radical scavenger edaravone(EDRV) on the production of reactive oxygen species in acute ischemia-reperfusion injured (I/RI) myocardium. METHODS: Male Sprague-Dawley rats, subjected to myocardial ischemia for 30 min and reperfusifor for 4 h, were divided into 5 groups: sham group, I/RI group, DIDS group, EDRV group and DIDS+EDRV group. The rats were treated with EDRV (10 mg/kg for 5 min) before reperfusion or/and DIDS (14 mg/kg,4 mL·kg^-1·h^-1 for 2 h) at the beginning of reperfusion by a program-controlled injection micropump . The myocardiac tissues were collected immediately at the end of reperfusion. The levels of ROS, OH· and O₂^- were determined by the methods of spectrofluorophotometry and colorimetry. Myocardial apoptosis was detected by TUNEL method. Serum superoxide dismutase (SOD) activity and malondialdehyde (MDA) concentration were measured by colorimetry. RESULTS: Compared with I/RI group, myocardial apoptotic index, the levels of ROS, O₂^-, OH· and MDA were significantly reduced, and SOD activity was significantly increased in DIDS group, EDRV group and DIDS+EDRV group (P<0.05). Compared with DIDS group, the levels of ROS,O₂^-, OH· and MDA were significantly decreased, and SOD activity was significantly increased in EDRV group (P<0.05).No statistical difference of myocardial apoptotic index between these two groups was observed (P>0.05). Compared with DIDS+ EDRV group, myocardial apoptotic index in DIDS group and EDRV group was significantly increased (P<0.05), and no significant difference of ROS, O₂^-, OH·, MDA and SOD between the two groups was found (P>0.05).CONCLUSION: DIDS and EDRV protect myocardial cells from apoptosis by inhibition of ROS activity. Combinative use of the two reagents has stronger cardioprotectiue effect, suggesting that they have different regulatory pathways.     

Apoptosis and its modulation in hepatic ischemia and reperfusion injury

Hepatic ischemia/reperfusion injury (HIRI) exists in lots of process of clinical pathology and operation. Apoptosis is an active process controlled by some gene and factors such as Fas/FasL, caspases and Bcl-2 families. More and more studies suggest that HIRI is associated with apoptosis. This article summarized the mechanisms and gene modulation of apoptosis during HIRI and the significance of suppressing apoptosis in preventing HIRI.