Effects Of Sevoflurane Preconditioning On Renal Ischemia-reperfusion Injury In Rats

Objective: To investigate the effects of sevoflurane pretreatment on renal ischemia-reperfusion injury in rats and related mechanisms of heat shock proteins 70.Methods: Twenty-four adult male Sprague-Dawley rats were randomly divided into three groups(n=8).(1)Sham group:Perform a similar operation without occlusion of renal blood flow.(2)I/R group:Perform the operation of partial renal ischemia- reperfusion(I/R).(3)SEV group:inhalation of 2.2% (1MAC) sevoflurane for 60 minute and washout for 10 minutes were performed before I/R.After 60 minutes of ischemia and 120 minutes of reperfusion,serum BUN,Cr,Cys C levels and MDA concentrations were measured.The kidney slices were also observed under microscope and electron microscope. At the same time,we used immuno-histochemistry staining for measuring expression of HSP70 of kidney tissues.Results: 1. There were no obvious difference in the serum BUN,Cr level of the three groups(P>0.05),while the serum Cys C level and MDA concentrations in I/R group were significantly higher than those in SHAM group(P<0.05), the serum level of Cys C and MDA concentrations in SEV group were lower than those in I/R group(P<0.05). 2. With the staining of HE, In SHAM group,it cannot be seen abnormality in both renal glomerulus and renal tubule. In I/R group,there were obvious stretch in proximal tubule and congested in renal interstitium, and many neutrophils gathered in renal interstitium. In SEV group, it cannot be seen obvious stretch in proximal tubule and congestion in renal interstitium.the Paller's score for actue renal tubular injury in I/R group increase markly compared with those in Sham group(P<0.05),which in SEV group decreased markly compared with those in I/R group(P<0.05). The transmission electron microscope(TEM) showed that in I/R group injuerd mitochondria were obviously swelled, serious vacuolar degeneration could be seen in renal tubular cell.In SEV group the cristae of mitochondria were slightly enchaged but the structure was still intact, The phenomenon of vacuolar degeneration was mitigated in renal tubular cell. In SEV group the injury of nephridial tissue was diminished significantly. 3.Results of HSP70 experssion showed that no positive staining in Sham group. In SEV group,it can be seen generally profound positive staining on endochylema and cellular nucleus. But in I/R group the positive area and intensity were much lower(P<0.05).Conclusions: 1.Pretreatment with 2.2% sevoflurane for 60 minutes and washout for 10 minutes can provide significant protection against renal ischemia-reperfusion injury. 2.The protective effects of sevoflurane pretreatment against renal ischemia-reperfusion injury may be related to the higher expression of HSP70 which can protect the cells directly and decrease the content of oxygen-derived free radidicals.