| Objective: To investigate the protective effect and the mechanism of action of Ginkgo biloba extract(EGb) on rat kidneys with ischemia-reperfusion injury(IRI), using models of rat kidneys with IRI.Methods: The models of renal ischemia/reperfusion in rats were set up with removal of right kidneys, and then clamping left renal pedicle to induce left kidney ischemia followed by reperfusion in situ. Thirty male wistar rats (weighing 200-300g) were randomly divided into three groups:①sham group;②IRI group(model group);③EGb-pretreated IRI group (treatment group). The levels of serum creatinine and urea nitrogen were measured; Besides, MDA levels and SOD activity were determined to assess tissue peroxidation and the pathomorphological changes in renal tissue was observed by HE staining. Terminal-deoxynucleotidyl transferase mediated nick end labeling(TUNEL) was used for testing apoptosis in renal tissue. Expression of Bcl-2 and Bax was detected by immunohistochemistry.Results:①The levels of serum creatinine and urea nitrogen in model group were obviously elevated, and significantly different from those in sham group(all P<0.01). In treatment group, the levels of serum creatinine and urea nitrogen were significantly lower compared with model group(all P<0.01), while higher than those of sham group(P <0.01) ;②After IRI, MDA levels in renal tissue increased significantly, whereas, SOD activity descended obviously, there were significant difference between model group and sham group(all P<0.01); In treatment group, MDA levels decreased and SOD activity was stepped up, which showed significant difference compared with model group(all P< 0.01), and no difference with sham group (all P>0.05) ;③Renal histopathology: There existed epithelial cells edema of renal tubule, vacuolization, tubule dilation, shrinkage of basement membranes,nuclear fragmentation and various tubule casts in model group, while all these histopathological changes were relieved in treatment group;④Little apoptosis in tubular epithelium were found in sham group, while apoptosis increased obviously in model group,apoptosis index were significantly higher than that of sham group(P<0.01); Nevertheless, there were notably less apoptosis and lower apoptosis index in treatment group compared with model group(P<0.05) Apoptosis index was higher in treatment group than in sham group (P<0.01) ;⑤.Compared with the results of sham group in which the expressions of Bcl-2 and Bax on renal tubules were slight, the expressions of Bcl-2 and Bax boosted in model group (Bcl-2: P<0.05, Bax:P<0.01) with descendent Bcl-2/Bax ratio (P<0.01); The treatment group showed a significantly higher expression of Bcl-2(P<0.01), along with decreased expression of Bax(P<0.05) and elevated Bcl-2/ Bax ratio(P<0.01).Conclusion: EGb pretreatment can attenuate SCr and BUN values, and renal tubule impairments after renal ischemia-reperfusion injury in rats, which indicates a protective effect on renal ischemia-reperfusion injury .The mechanism may be associated with its capabilities of anti-oxygen free radicals, anti-peroxidation and inhibition of apoptosis( affect the expressions of Bcl-2 and Bax).
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