脓毒症致大鼠急性肾损伤中炎症介质的变化及机制探讨

Effect of inflammatory mediators on sepsis-induced acute kidney injury in rats and its mechanism

目的观察脓毒症致大鼠急性肾损伤(AKI)中血清和肾脏组织中炎症介质的变化及肾脏组织中核因子-κB(NF-κB)的表达,探讨脓毒症致大鼠急性肾损伤的可能机制。方法雄性SD大鼠随机分为假手术组(Sham组)和盲肠结扎穿孔组(CLP组)。CLP组大鼠采用盲肠结扎穿孔法建立脓毒症动物模型,Sham组除不结扎穿孔盲肠外,其余处理同脓毒症组。分别于造模后6h、12h和24h观察各组大鼠血清肿瘤坏死因子-α(TNF-α)和白介素-6(IL-6)水平,肾脏组织中Toll样受体4(TLR4)和高迁移率族蛋白B1(HMGB1)mRNA表达;免疫组化法检测肾小管中NF-κB p65的表达,分析NF-κB p65核阳性率。结果与相同时间点Sham组比较,CLP组6h^12h大鼠血清TNF-α和IL-6水平明显升高(P<0.01),CLP组6h^24h大鼠肾脏组织中TLR4mRNA表达明显升高(P<0.01),CLP组12h^24h大鼠肾脏组织中HMGB1mRNA表达明显升高(P<0.01),CLP组6h^24h大鼠肾小管中NF-κB p65核阳性率升高(P<0.05~P<0.01)。结论随脓毒症致AKI病程的延长,大鼠肾脏组织中TLR4和HMGB1mRNA表达和NF-κB p65核阳性率明显升高,其机制可能与TLR4介导的炎症通路密切相关。

Objective To observe the inflammatory mediators and nuclear factorκB(NF-κB)expression in serum and kidney tissue of rats with sepsis-induced acute kidney injury,and explore the possible mechanisms of such injury.Methods Male SD rats were randomly divided into a sham operation group(Sham group)and a cecal ligation and puncture group(CLP group).The rat model of sepsis was established by cecal ligation and puncture in the CLP group,but the Sham group didn't undergo cecal ligation and puncture.The levels of tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)in the serum,the expressions of Toll-like receptor 4(TLR4)and high mobility group box 1protein(HMGB1)mRNA in kidney tissue of the 2groups were observed at 6,12and 24hours after operation.The expression of NF-κB p65in renal tubules was observed by immunohistochemical staining to calculate its nuclear positive rate.Results Compared with those of time-matched Sham group,the levels of TNF-αand IL-6in the CLP group were significantly higher at 6hto 12h(P<0.01),the expression of TLR4mRNA the was increased at 6to 24h(P<0.01),the expression of HMGB1mRNA was increased at 12to 24h(P<0.01), and the nuclear positive rate of NF-κB p65was increased at 6to 24h(P<0.05to P<0.01).Conclusion During the course of sepsis-induced acute kidney injury,the expressions of TLR4mRNA and HMGB1mRNA and the nuclear positive rate of NF-κB p65were significantly higher in kidney tissue,and the mechanism may be closely related to TLR4-mediated inflammatory signaling pathways.