Protective Effects Of Caspase-3 Inhibitor On Mice Kidneys With Ischemia/reperfusion Injury: An Experimental Study

[Objective]To explore the protective effect of caspase-3 inhibitor(Ac-DEVD-CHO) on kidneys with ischemia/reperfusion(I/R) injury and study initially its possible mechanism.[Methods]1.The models of renal ischemia/reperfusion in mice were set up with removal of right kidneys,and then clamping left renal pedicles to induce left kidneys ischemia followed by reperfusion in situ.2.Thirty male Kunming-mice were divided randomly into three groups:sham group,I/R group and treatment group with Ac-DEVD-CHO.At the time of reperfusion after ischemia for 45 minutes,mice of treatment group were injected via tail vein Ac-DEVD-CHO(4μg/g) dissolved in 0.3mL normal saline,mixed with 1%v/v dimethylsulfoxide(DMSO).In I/R group,mice were administered 0.3mL normal saline containing 1%v/v DMSO when reperfusing.Sham group was treated as same as I/R group without clamping the renal pedicle.Twelve hours after reperfusion,the blood samples were collected by removing the eyeballs to detect the levels of serum creatinine (Cr) and blood urea nitrogen(BUN).The left kidneys were harvested to detect the activities of caspase-3 and Myeloperoxidase(MPO) by colorimetric method,and to measure apopotosis by TUNEL method.The expression of ICAM-1 protein in renal tissue was detected by immunohistochemistry,and the pathomorphological changes in renal tissue were observed by HE staining.[Results]The structure of renal tissue in sham group was essentially normal.In I/R group, we saw obvious degeneration and necrosis inside the renal tubular epithelial cells,and also found notable expansion of lumens and infiltration of leukocytes In contrast to I/R group,the pathomorphological changes were alleviated markly in treatment group. Compared with sham group,the levels of serum Cr and BUN,the apoptotic index,the activities of caspase-3 and MPO,and the expression of ICAM-1 were all obviously increased in I/R group(P＜0.01).In treatment group,the levels of serum Cr and BUN, the activity of caspase-3,and the apoptotic index were all significantly decreased in contrast to the I/R group(P＜0.01).The activity of MPO and the expression of ICAM-1 in treatment group were also lower than those in the I/R group(P＜0.05).We also found that all indexes except the acticity of caspase-3(P＞0.05)were different between treatment group and sham group(P＜0.01).[Conclusion]1.The models of renal I/R injury in mice are set up successfully.Renal function and structure are worsened at early time after I/R injury.2.The treatment with Ac-DEVD-CHO at the time of reperfusion can alleviate the renal I/R injury.The protective mechanism may be due to inhibiting the activity of caspase-3 to reduce apoptosis and down-regulate the expression of ICAM-1 which mediates the inflammatory reaction.