Objective  To investigate the effect and mechanism of pretreatment with allopurinol on renal ischemia-reperfusion injury(IRI) in rats.

  Methods  Twenty four rats were randomly assigned into the sham operation (S), ischemia-reperfusion (IR) and allopurinol pretreatment (APC) groups (n=8 for each group). At preoperative 2 weeks, allopurinol at a dose of 50 mg/(kg·d) was administered via intraperitoneal injection in the APC group, and an equivalent quantity of physiological saline was given via intraperitoneal injection in the S and IR groups. After pretreatment, the right kidneys of rats in the S group were resected. In the IR and APC groups, the right kidneys were resected and the left kidneys were treated with 30 min ischemia-reperfusion. Blood sample was collected at 24 h after reperfusion and the kidney specimen was obtained at postoperative 2 weeks. The levels of blood urea nitrogen (BUN) and serum creatinine (Scr) were detected by automatic biochemistry analyzer. The activity of plasma malondialdehyde (MDA) and superoxide dismutase (SOD) was respectively assessed by detection kits. The expression levels of Bax, Bcl-2 and Caspase-3 of rat kidney were measured by western blot. Pathological changes in the rat kidney were observed under light microscope. Cell apoptosis of rat kidney was evaluated by TdT mediated-dUTP nick end labeling (TUNEL).

  Results  Compared with the S group, the levels of BUN, Scr and plasma MDA in the IR and APC groups were significantly increased, whereas the activity of plasma SOD was significantly reduced(all in P < 0.05). Compared with the IR group, the levels of BUN, Scr and plasma MDA in the APC group were significantly reduced, whereas the activity of plasma SOD was considerably elevated (all in P < 0.05). Compared with the S group, the expression levels of Bax and Caspase-3 proteins were significantly up-regulated in the IR and APC groups, and the levels in the APC group were considerably lower than those in the IR group (all in P < 0.05). Compared with the S group, the expression of Bcl-2 in rat kidney in the IR and APC groups was significantly down-regulated, and the value in the APC group was dramatically higher than that in the IR group (all in P < 0.05). Under light microscope, the morphology of rat kidney was intact and normal in the S group. In the IR group, evident renal tubular ectasia, massive necrosis of renal tubular epithelial cells, evident stromal edema and a large quantity of lymph cellular infiltration were observed. In the APC group, mild renal tubular ectasia was observed, whereas no apparent kidney stromal edema was noted. A slight amount of lymph cellular infiltration was noted in the stroma. TUNEL staining revealed that the apoptosis rate of kidney cells in the S, IR and APC groups was (4.1±1.7)%, (32.8±8.9)% and (12.6±3.4)% (all in P < 0.05).

  Conclusions  Allopurinol pretreatment could suppress cell apoptosis through anti-oxidation effect, thereby alleviating IRI of rat kidney and improving renal function.