Protection against renal ischaemia/reperfusion injury: A comparative experimental study of the effect of ischaemic preconditioning vs. postconditioning

Objective: To compare the effect of ischaemic preconditioning (Ipre) vs. ischaemic postconditioning (Ipost) on renal ischaemia/reperfusion (I/R) injury in rats. Materials and methods: In all, 120 male Sprague–Dawley rats were classified into four groups of 30 rats each, designated sham, control, Ipre and Ipost. Renal func- tion, including serum creatinine, blood urea nitrogen (BUN), creatinine clearance (CrCl), fractional Na excretion (FENa) and renal histopathology were measured at 2, 24 and 48 h after ischaemia. Markers of lipid peroxidation (malondialdehyde, MDA), superoxide dismutase (SOD) and reduced glutathione (GSH) were measured in kidney tissues during the same intervals. Results: Ipre caused a significant improvement in renal function, as indicated by a significant decrease in serum creatinine, BUN and FENa, with a significant increase in CrCl. However, Ipost caused no significant improvement in renal function. Morphologically Ipre caused a marked significant improvement in the renal tubular damage score compared to Ipost. Also, Ipre caused a significant decrease in MDA, and significant increase in GSH and SOD when compared to Ipost. Conclusion: Ipre is more potent than Ipost for improving the renal injury induced by I/R. Ipre caused a marked improvement in renal function and morphology, while Ipost caused a minimal improvement in morphology only. Moreover, Ipre caused a marked and significant reduction in oxidative stress in kidney tissues, while Ipost caused a minimal reduction.