Effects of isoflurane preconditioning on renal ischemia-reperfusion injury in rats

Abstract

Objective To investigate the effects of isoflurane preconditioning on renal ischemia reperfusion (I/R) injury in rats and the role of TNF-α plays in the mechanism.Methods Male SD rats were used in the study.The animals were randomly divided into 3 groups ( n =12 each):shame operation group; I/R group; Isoflurane preconditioning group (inhaled 1.5％ isoflurane (1 MAC) for 30 min followed by 10 min washout before I/R).At 2 h reperfusion,blood samples were obtained for urea nitrogen (BUN) concentration and creatinine (Cr) content.The level of TNF-α in renal tissues were determined by enzyme-linked immunosorbent assay (ELISA).Observe the pathological changes in H.E.staining slides under microscope.Results BUN concentration and Cr content and the level of TNF-α in I/R group and isoflurane preconditioning group were significantly higher than in shame operation group[ BUN:( 17.69 ±0.99)mmol/L vs (8.37 ±1.12)mmol/L,t =-23.55,P ＜0.01; ( 12.26 ± 1.11 ) mmol/L vs (8.37 ±1.12 )mmol/L,t =- 19.09,P ＜ 0.01 ;Cr:( 103.22 ± 13.42)μmol/L vs (71.48 ± 8.59) μ mol/L,t =-21.45,P ＜0.01;(86.51 ± 11.49) μmol/L vs (71.48 ±8.59) μmol/L,t =-9.87,P ＜0.01 ;TNF-α:(0.51 ±0.07)ng/ml vs (0.43 ±0.00)ng/ml,t =-5.79,P ＜0.01;(0.47 ±0.03)ng/ml vs (0.43 ±0.00)ng/ml,t =-8.86,P ＜0.01 ].BUN concentration and Cr content and the level of TNF-α in Isoflurane preconditioning group were significantly lower than in I/R group [ BUN:( 12.26 ± 1.1 1 ) mmol/L vs ( 17.69 ± 0.99 ) mmol/L,t =15.67,P ＜ 0.01 ; Cr:( 86.51 ± 11.49) μmol/L vs ( 103.22 ± 13.42 ) μ mol/L,t =6.68,P ＜0.01 ;TNF-α:(0.47 ±0.03) ng/ml vs (0.51 ±0.07) ng/ml,t =2.61,P ＜0.05].Therenal I/R injury which located around kidney tubules was increased in I/R group and isoflurane precondi-tioning group compared to shame operation group [ ( 17.26 ± 1.45 ) vs (0.00 ± 0.00 ),t =- 72.38,P ＜0.01;(12.69±1.83) vs (0.00 ±0.00),t =-39.53,P ＜0.01].The renal I/R injury which located around kidney tubules was decreased in isoflurane preconditioning group compared to I/R group [ ( 12.69 ±1.83) vs (17.26±1.45),t =19.87,P ＜0.01].Conclusions Preconditioning with 1.5％ isoflurane 30 min can protect kidney from I/R injury in rats by regulating the level of TNF-α in renal tissues. Key words: Isoflurane/pharmacology; Tumor necrosis factor-alpha/metabolism; Kidney/pathol-gy; lschemic preconditioning; Reperfusion injury; Rats