Objective To investigate the effects of preconditioning with repeated electroacupuncture (EA)at Shenshu acupoint on renal ischemia-reperfusion (I/R) injury in rats.Methods Fifty adult male Sprague-Dawley rats,weighing 260-320 g,were randomly divided into 4 groups:sham operation group (n =5),I/R group,pentobarbital sodium + I/R group (PB + I/R group) and repeated EA at Shenshu acupoint + I/R group (EA + I/R group).The model of renal I/R injury was established by occlusion of bilateral renal pedicles for 45 min followed by reperfusion.Pentobarbital sodium 30 mg/kg was injected intraperitoneally everyday for 5 consecutive days and I/R was induced 24 h after the last injection in PB + I/R group.The animals received EA at Shenshu acupiont 30min per day for 5 consecutive days under pentobarbital sodium anesthesia and I/R was induced 24 h after the last preconditioning in EA + I/R group.Blood samples were taken at 1,3 and 7 days after I/R to determine the levels of serum blood urea nitrogen (BUN) and creatinine (Cr).The animals were then sacrificed and the kidney was isolated.The histological changes of the kidney was scored.The apoptosis in renal tubular epithelial cells was measured using TUNEL at 3 days after I/R.Apoptosis index (AI) was calculated.The expression of proliferating cell nuclear antigen (PCNA),Bcl-2,Bax,Fas and FasL in renal tubular epithelial cells was measured by immuno-histochemistry at 3 days after I/R.Results Compared with group S,the levels of serum BUN and Cr,and histological score were significantly increased at 1,3 and 7 days after I/R in I/R and PB + I/R groups,and at 1 and 3 days after I/R in EA + I/R group,the expression of PCNA,Bcl-2,Bax,Fas and FasL was up-regulated in I/R,PB + I/R and EA + I/R groups,and Bax/Bcl-2 ratio was significantly increased in I/R and PB + I/R groups (P ＜0.05).Compared with I/R and PB + I/R groups,the levels of serum BUN and Cr,and histological score were significantly decreased at 3 and 7 days after I/R,AI and the expression of Bax,Fas and FasL were significantly decreased,and the expression of PCNA and Bcl-2 was up-regulated in EA + I/R group (P ＜ 0.05).Conclusion Preconditioning with repeated EA at Shenshu acupoint can attenuate the renal I/R injury in rats by promoting the proliferation of renal tubular epithelial cells and reducing the apoptosis in cells.