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.

Landfill is one of the important sources of carbon tetrachloride (CT) pollution, and it is important to understand the degradation mechanism of CT in landfill cover for better control. In this study, a simulated landfill cover system was set up, and the biotransformation mechanism of CT and the associated micro-ecology were investigated. The results showed that three stable functional zones along the depth, i.e., aerobic zone (0-15 cm), anoxic zone (15-45 cm) and anaerobic zone (> 45 cm), were generated because of long-term biological oxidation in landfill cover. There were significant differences in redox condition and microbial community structure in each zone, which provided microbial resources and favorable conditions for CT degradation. The results of biodegradation indicated that dechlorination of CT produced chloroform (CF), dichloromethane (DCM) and Cl^- in anaerobic and anoxic zones. The highest concentration of dechlorination products occurred at 30 cm, which were degraded rapidly in aerobic zone. In addition, CT degradation rate was 13.2-103.6 μg/(m²·d), which decreased with the increase of landfill gas flux. The analysis of diversity sequencing revealed that Mesorhizobium, Thiobacillus and Intrasporangium were potential CT-degraders in aerobic, anaerobic and anoxic zone, respectively. Moreover, six species of dechlorination bacteria and eighteen species of methanotrophs were also responsible for anaerobic transformation of CT and aerobic degradation of CF and DCM, respectively. Interestingly, anaerobic dechlorination and aerobic transformation occurred simultaneously in the anoxic zone in landfill cover. Furthermore, analysis of degradation mechanism suggested that generation of stable anaerobic-anoxic-aerobic zone by regulation was very important for the harmless removal of full halogenated hydrocarbon in vadose zone, and the increase of anoxic zone scale enhanced their removal. These results provide theoretical guidance for the removal of chlorinated pollutants in landfills.
Bacteria/metabolism* ; Biodegradation, Environmental ; Carbon Tetrachloride/metabolism* ; Methane/metabolism* ; Waste Disposal Facilities