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.     

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.     

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.     

Molecular mechanisms of liver regeneration following cold ischemia injury after liver transplantation in rat

AIM: To study the molecular mechanisms of liver regeneration following different cold ischemia (CI) times after liver transplantation in a rat model. METHODS: A model of rat orthotopic liver transplantation was established. The rats were divided into 3 groups: 1 h CI group, 8 h CI group and 16 h CI group. Survival rate in each group was recorded. Specimen were collected at predetermined intervals from 90 min, 1, 4 and 7 d post-reperfusion. The patterns of TNF-α, IL-6 and STAT3 activation were determined in liver grafts with 1 h, 8 h and 16 h CI times. Expression of cyclin D1 and hepatocyte replication with bromodeoxyuridine (BrdU) were confirmed by immunohistochemistry. The results of TNF-α and IL-6 expression in all groups were analyzed after whole liver transplantation. Statistical analysis was used to compare BrdU positively stained hepatocytes at 48 h post-reperfusion. RESULTS: Liver transplantation was successfully performed in all experimental groups. Survival rate in each group was 100% (>14 d). Compared with 1 h CI, TNF-α expressions in whole liver grafts with 8 h and 16 h CI were markedly increased at 90 min after reperfusion(P<0.05). Compared with 1 and 8 h CI, IL-6 expression in liver grafts preserved for 16 h were markedly increased at 90 min after transplantation (P<0.05). With 8 and 16 h CI, STAT3 activity was markedly increased. Cyclin D1 expression in 8 CI group was demonstrated with cytoplasmic and nuclear staining at 24 h in liver grafts. Cyclin D1 expression was mainly nuclear in 16 h CI group. Extensive hepatocyte replication was present. The numbers of hepatocytes with positively stained nuclei in 16 h CI group were more than those in 1 and 8 h CI group at 48 h after transplantation(P<0.05). CONCLUSION: Rat whole liver grafts with 16 h CI injury still initiate and complete liver regeneration and graft recovery after liver transplantation. Liver regeneration following transplantation may be through TNF-α/IL-6/STAT3/cyclin D1/DNA synthesis pathways.     

Changes of cardiac energy metabolism and structure during ischemia/reperfusion injury of liver in rats

AIM: To investigate the effect and mechanism of liver ischemia/reperfusion (I/R) injury on the changes of cardiac energy metabolism and structure.METHODS: 48 healthy Wistar male rats were randomly divided into 6 groups as follows (n=8 in each group): control group (CTL), simply ischemia for 30 min without reperfusion(I group); reperfusion following ischemia for 30 min (I/R group); 2 h reperfusion following ischemia for 30 min (I/R 2 h group); 4 h reperfusion following ischemia for 30 min (I/R 4 h group) and 6 h reperfusion following ischemia for 30 min (I/R 6 h group). The level of serum endotoxin was measured. The levels of insulin and insulin antibody in heart were detected by radioimmunoassay. The contents of MDA, MPO and lactic acid in heart were also determined. RESULTS: During the process of liver I/R injury, the level of endotoxin increased in I group and I/R group and declined gradually for long time during reperfusion, but was still longer than that in CTL group (P<0.05). The level of MDA obviously increased in I group and in all reperfusion groups compared to CTL (P<0.05). The obvious significant differences among I/R 2 h group, I/R 4 h group, I/R 6 h group with CTL were observed (P<0.05). The activities of MPO obviously increased in all reperfusion groups, there was also an obvious significant difference compared with CTL and I group (P<0.05). The level of lactic acid obviously increased with prolongation in reperfusion (P<0.05), but decreased in I/R 6 h group (P<0.05). The level of insulin decreased in I/R 4 h group and I/R 6 h group (P<0.05). No difference of insulin antibody was observed among all groups (P>0.05). CONCLUSION: During the process of liver I/R injury, endotoxin is absorbed from intestine and impairment of liver detoxication leads to endotoxemia, which might play a role in the changes of the energy metabolism and structure in heart.     

Knockdown of Atg5 aggravates cerebral ischemia and reperfusion injury in mice

AIM: To study the role of autophagy-related gene 5 (Atg5) in cerebral ischemia and reperfusion injury in mice. METHODS: BALB/c male mice (weighing 18~22 g) were randomly divided into sham group, ischemia/reperfusion (I/R) group, Atg5 siRNA group and control siRNA group. Focal cerebral ischemia was performed using the method of middle cerebral artery occlusion (MCAO) for 60 min and reperfusion for 24 h. In siRNA group and control group, 5 μL Atg5 siRNA or scrambled siRNA was administered by intracerebroventricular injection 24 h before MCAO. The expression of Atg5 at mRNA and protein levels in ischemic cortex at 24 h after reperfusion was determined by real-time PCR and Western blot. The infarct volume and edema were evaluated by TTC staining, and motor deficits were evaluated by neurological scoring. RESULTS: The expression of Atg5 at mRNA and protein levels was significantly increased 24 h after reperfusion in I/R group compared with sham group. Atg5 siRNA obviously decreased the expression of Atg5 at mRNA and protein levels induced by I/R. Inhibition of Atg5 exacerbated the infarct volume and ameliorated the neurological symptoms. CONCLUSION: Atg5 has neuroprotective effect on focal cerebral ischemia and reperfusion injury.     

Effects of ischemic preconditioning on hepatocyte apoptosis induced by hepatic ischemia-reperfusion in cirrhotic rats

AIM:To investigate the protective effect of ischemic preconditioning (IPC) on hepatic ischemia-reperfusion(I/R) injury in cirrhotic rats and its possible mechanism. METHODS:Hepatic I/R was induced by Pringle maneuver. The cirrhotic rats were randomized into three groups: Group A: before 30 min of ischemia, a short period of 5 min ischemia and 5 min reperfusion were given; Group B: before 30 min of ischemia, a short period of 10 min ischemia and 10 min of reperfusion were given; Group C: 30 min ischemia only. The serum alanine transferase (ALT), hepatic Fas-mRNA, caspase-3 activity and hepatocyte apoptosis were analyzed. RESULTS:The 7-day survival rate in the group A and B were 100%, respectively. However, it was only 62.5% in the group C. After 6 h of reperfusion, the ALT levels in both group A and B were significantly lower than that of in group C, P＜0.01. The ALT level of group A was also lower than that of group B, P＜0.01. The hepatic Fas-mRNA expression, caspase-3 activity and apoptotic hepatocyte in group A were significantly lower than those of in group C, P＜0.01. CONCLUSIONS:IPC has significant protective effect against hepatic I/R injury. An IPC with 5 min of ischemia and 5 min of reperfusion has the maximal protective effect. The protective mechanism of IPC against hepatic I/R injury is via down-regulation of Fas-mRNA expression, inhibiting caspase-3 activity and subsequently inhibiting hepatocyte apoptosis.     

Knockdown of astrocyte elevated gene-1 by siRNA inhibits cell proliferation and induces apoptosis in human neuroblastoma cell line

AIM: To investigate the effect of siRNA-induced astrocyte elevated gene-1 ( AEG-1 ) down-regulation on the proliferation, apoptosis and cell cycle of neuroblastoma cells. METHODS: An siRNA targeting to AEG-1 mRNA (AEG-1 siRNA) was constructed and transfected into neuroblastoma cells with Lipofectamine 2000. A non-specific siRNA (control siRNA) and non-treatment were used as negative control and blank control,respectively . The cell proliferation was detected by MTT method and colony formation assay. The apoptosis and cell cycle were analyzed by flow cytometry. RESULTS: Compared with control groups, the expression of AEG-1 mRNA was evidently declined in the cells transfected with AEG-1 siRNAs (P<0.05). AEG-1 siRNA significantly decreased the cell proliferation. After treated with AEG-1 siRNA for 48 h, the percentage of apoptotic cells was significant increased and the cell cycle was arrested in G₀/G₁ phase compared with the control cells (P<0.05). CONCLUSION: The mRNA expression of AEG-1 is down-regulated by AEG-1 siRNA in neuroblastoma cells. Knockdown of AEG-1 expression in human neuroblastoma cells significantly inhibits cell proliferation and apoptosis, and induces cell arrest in G₀/G₁ phase of the cell cycle.     

Effect of RICTOR expression on cell viability in rheumatoid arthritis fibroblast-like synoviocytes

AIM：To investigate the effects of RICTOR expression on the viability of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS). METHODS：RA-FLS were obtained by tissue culture. Chemically synthesized double-stranded siRNAs targeting RICTOR gene were transfected into RA-FLS by cationic liposome. The nonspecific siRNA was also transfected into the negative control cells. The mRNA expression of RICTOR was detected by RT-qPCR after transfection for 24 h. Western blotting was used to evaluate the inhibitory effects of siRNAs on RICTOR expression after transfection for 48 h and 72 h. The cell viability was examined by MTT assay. RESULTS：Compared with control group, the mRNA expression of RICTOR significantly decreased by 78.36%±3.71% after the transfection of RICTOR siRNA for 24 h. The protein level of RICTOR was also obviously lower in RICTOR siRNA transfection group than that in control group after transfection for 48 h (decreased by 92.48%±6.14%) and 72 h (decreased by 98.57%±1.40%). Knock-down of RICTOR in RA-FLS for 72 h markedly decreased the cell viability. CONCLUSION：Transfection of RICTOR siRNA reduces the viability of RA-FLS, indicating that mTORC2 may be required for the survival of RA-FLS.     

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.     

Ischemic preconditioning protects against hepatic ischemia-reperfusion injury by attenuating leukotriene C4 production

AIM：To investigate the effect of ischemic preconditioning (IP) on leukotriene C4 (LTC4) generation during hepatic ischemia-reperfusion(I/R) injury.METHODS：Adult male Sprague-Dawley rats were randomly divided into sham (control) group, I/R group and IP+I/R group. The rat liver was subject to 60 min of partial hepatic ischemia followed by 5 h of reperfusion. LTC4 content was measured by reversed-phase high-performance liquid chromatography (RP-HPLC). The activity of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was determined, and the changes of histological structures were observed to assess the tissue injury. The reduced glutathione (GSH) level in the liver tissues was also examined by biochemical methods.RESULTS：IP markedly decreased LTC4 content in rat livers compared with I/R group. The activity of serum ALT and AST in I/R group and IP+I/R group was higher than that in control group. Compared with I/R group, the levels of serum ALT and AST were markedly decreased, and the level of GSH in hepatic tissues was elevated in IP+I/R group. In addition, the structural damage of the rat liver tissues in IP+I/R group displayed slighter than that in I/R group.CONCLUSION：IP treatment reduces LTC4 production accompanied with improving the liver function and histological structure during I/R injury, suggesting that the beneficial effects of IP may be involved in its repressing LTC4 generation during hepatic I/R injury.     

Intrathymic inoculation of liver specific antigen protects hepatocytes from apoptosis after liver allotransplantation

AIM: To study the effects of intrathymic inoculation of liver specific antigen (LSA) on hepatocyte apoptosis after liver allotransplantation. METHODS: Orthotopic liver transplantation was used in this study. Group Ⅰ: syngenic control (Wistar-to-Wistar); Group Ⅱ: acute rejection (SD-to-Wistar); Group Ⅲ: thymus inoculation of SD rat LSA day 7 before transplantation. The observation of general situation and survival time, hepatocyte apoptosis and LAT expression in liver transplants were used to analyze immune state of animals in different groups. RESULTS: The general situation of group Ⅰ was very well after transplantation. Recipients of groupⅡ lost body weight progressively and all died within day 9 to day 13 post transplantation. As for group Ⅲ, the general situation of recipients was remarkably better than that in group Ⅱ. The positive cells of apoptosis in group Ⅲ detected by TUNEL were not significantly different from that in group Ⅰ, but was significantly lower than that in group Ⅱ. LAT was detected at any time in group Ⅱ with peak expression at day 5 and day 7 post transplantation. In contrast, LAT was not detected in any other groups. CONCLUSION: Intrathymic inoculation of LSA protects hepatocytes from apoptosis after liver allotransplantation.     

LPS preconditioning relieves chronic liver injury induced by carbon tetrachloride

AIM:To investigate the effect of lipopolysaccharides(LPS)preconditioning on CCl4-induced liver injury and the change of LPS signal transduction.METHODS:The male Wistar rats were divided randomly into liver-injury group, which were injected with CCl4 5 mL/kg first, three days later were injected 0.3 mL 40% CCl4 and 60% olive oil.Animals in LPS preconditioning group were injected with LPS 0.5 mg/kg before the day CCl4 was given.Rats received high fat diet were as liver injury group, and normal control group received normal diet.The lymphocytes infiltrated in the liver tissue were counted.The endotoxin and ALT level in rat plasma, TNF-α content and expressions of TLR4, p38, p-p38, IκΒ, NF-κΒ in the rat livers were also determined.RESULTS:The lymphocytes in liver slice and ALT level of the plasma in LPS preconditioning group were lower significantly than those in the liver injury group, and the expressions of TLR4, p-p38, NF-κΒ in the liver were the same.In contrast, the expression of IκΒ was higher.CONCLUSION:LPS preconditioning relieves obviously CCl4-induced chronic liver injury.The mechanism may be associated with change of signal transduction of LPS, which results in decrease of pre-inflammatory cytokines.     

Role of endoplasmic reticulum stress in Bim-mediated cardiomyocyte apoptosis induced by hypoxia

AIM:To investigate the role of endoplasmic reticulum stress (ERS) in the process of Bim-mediated cardiomyocyte apoptosis induced by hypoxia. METHODS:Cardiomyocytes were isolated from neonatal Sprague-Dawley rats aged 1~3 days, and primarily cultured in vitro. The antibody targeting α-striated muscle actin was used to identify the cardiomyocytes. The siRNAs targeting bim were transfected into cardiomyocytes with liposome, followed by detecting the expression of Bim by Western blotting. Cardiomyocytes were divided into five groups: blank control group, hypoxia group, hypoxia+liposome group, hypoxia+negative control siRNA group and hypoxia+Bim-siRNA group. The cell viability was determined by MTT assay, and the cell apoptotic rate and the intracellular calcium concentration were measured by flow cytometry. The protein expression of caspase-12 and inositol 1,4,5-triphosphate (IP3) was detected by Western blotting. RESULTS:Immunohistochemical identification confirmed that rat cardiomyocytes were successfully cultured. Green fluorescence was observed in the cells transfected with negative control siRNA under fluorescence microscope. The expression of Bim was obviously inhibited after transfected with Bim-siRNAs and the silencing efficiency of Bim-siRNA-2 was the highest (86.73%). Compared with blank control group, the viability of cardiomyocytes in hypoxia group was significantly reduced (P<005). Compared with hypoxia+negative control siRNA group, the viability of cardiomyocytes in hypoxia+Bim-siRNA group was significantly increased (P<005). The apoptotic rate and the intracellular calcium concentration of cardiomyocytes were obviously increased in hypoxia group (P<0.01), and were both decreased after bim silencing (P<005 or P<0.01). The expression of caspase-12 and IP3 was up-regulated in hypoxia group (P<005), and was down-regulated after bim silencing (P<005 or P<0.01). CONCLUSION: Cardiomyocyte apoptosis induced by hypoxia can be inhibited by silencing the expression of bim gene. Caspase-12 and IP3, as markers of ERS, may participate in the process of Bim-mediated cardiomyocyte apoptosis induced by hypoxia.     

Pretreatment of hypertonic saline attenuates the hepatic ischemia reperfusion injury induced by neutrophils

AIM: To explore the effect of the pretreatment of hypertonic saline (HTS) in hepatic ischemia reperfusion (I/R) injury.METHODS: The rats were divided into sham group (sham group), ischemia reperfusion group (IR group) and pretreatment of hypertonic saline group (HTS group). Partial hepatic ischemia reperfusion model was used. The rats were sacrificed at the time of 1 h, 3 h, 6 h, 12 h and 24 h after reperfusion in each group, respectively. Blood samples were obtained to examine ALT. The expression of the CD11b/CD18 (Mac-1) on the neutrophils was analyzed by flow cytometry. RT-PCR and Western blotting were used to examine the expression of intercellular adhesion molecule-1 (ICAM-1) in livers and chromatometry was performed to detect the activity of myeloperoxidase (MPO) in livers. The morphology of hepatocytes and the structure of sinusoid were observed by histological examinations. RESULTS: ① HTS pretreatment decreased the level of ALT at the time points of 3 h, 6 h and 12 h after reperfusion (P<0.05). ② Mac-1 expression in HTS group was lower at 6 h and 12 h after reperfusion compared with IR group (P<0.05). ③ MPO activity in HTS group was lower at 6 h, 12 h and 24 h compared with IR group (P<0.05). ④ RT-PCR and Western blotting analysis indicated that the pretreatment of HTS inhibited the expression of ICAM-1 in livers after reperfusion. ⑤ Moderate hepatocyte swelling and few neutrophil infiltration were observed in HTS group.CONCLUSION: Pretreatment with HTS has the effect on hepatic ischemia reperfusion injury by inhibiting the expression of Mac-1 on circulating neutrophils and the expression of ICAM-1 in the liver.     

Effect of tacrolimus on renal ischemia/reperfusion injury in rats

AIM: To investigate the protective effects and mechanism of tacrolimus on renal ischemia/reperfusion(I/R) injury in rats.METHODS: Sixty male Wistar rats were randomly divided into 3 groups: sham-operated group, I/R group and tacrolimus group. After the renal I/R injury model was established, the serum content of creatinine(Cr), tumor necrosis factor-α(TNF-α)and malondialdehyde(MDA) and activity of superoxide dismutase(SOD) were measured at reperfusion time points of 0.5 h, 2 h, 6 h and 24 h. The renal histopathological lesions and the expression of Fas and caspase-3 were observed by the methods of microscopy and immunohistochemistry, respectively.RESULTS: At all the 4 time points, the levels of Cr, TNF-α and MDA in tacrolimus group were lower than those in I/R group(P<0.05). The SOD activity in tacrolimus group was higher than that in I/R group. Compared with I/R group, the renal histopathological lesions were improved, and the levels of Fas and caspase-3 were significantly decreased in tacrolimus group(P<0. 05).CONCLUSION: Tacrolimus inhibits the production of free radical, the expression of TNF-α and apoptosis of renal tubular epithelial cells in renal I/R injury in rats, indicating that tacrolimus has protective function against renal I/R injury.