Effect of renal ischemic preconditioning on the activity of NF-κB and cells apoptosis

Objective To investigate the effect of different modes of renal ischemia on the activity of NF-κB and the composition of dimeric subunit and to explore the causative mechanism underlying the attenuated apoptosis of renal tubular cells with the establishment of animal models of acute renal ischemic/reperfusion(I/R) and ischemic preconditioning(I/P+I/R) in rats.Methods 30 male Sprague-Dawley rats were randomized into 3 groups(n=10 each) following right nephrectomy and isolation of the left renal artery.Group A served as the sham-operated control,only with isolation of the left renal artery and suture following exposure for 60 min.Group B(I/R group) rats were subjected to ischemia for 45 min by clamping of the left renal artery and subsequent resumed blood supply.Group C(I/P+I/R) rats were pre-treated with 3 cycles of 2-minute ischemia and 5-minute reperfusion.All the rats were sacrificed at 24 h and nephrectomy was performed for analysis,including biochemical determination of the serum creatinine,histopathological evaluation of the renal tubules,electrophoretic mobility shift assay(EMSA) of renal NF-кB/DNA binding activity,super shift assay of the composition of NF-κB complexes in renal tissues and terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL) assay of the apoptosis of renal tubular epithelial cells.Results Serological examinations and scores of renal tubular injury revealed evident histopatological changes and serious injury in renal tissues in group B.Compared with the sham group,the differences were statistically significant(P0.05);Compared with group B,group C had markedly attenuated injury with significant statistical differences(P0.05);EMSA results showed that the renal NF-кB/DNA binding activity was significantly higher in group C than in group A,with significant statistical differences(P0.05);and super shift assay of the composition of NF-κB dimeric subunit confirmed the presence of p65 and p50 in group C,with significant statistical differences(P0.05).Conclusion Renal ischemic preconditioning attenuates the apoptosis of renal tubular epithelial cells via the inhibition of the transcriptional activity of NF-кB,and thus has the protective effect on renal tissues.