Notch通路在大鼠肾脏缺血再灌注损伤TLR4介导的炎症反应中的作用

 目的: 探讨Notch通路对大鼠肾脏缺血再灌注损伤(IRI)中Toll样受体4(TLR4)介导的炎症反应的作用。方法: 雄性SD大鼠75只随机分为假手术组(sham组)、缺血再灌注组(IRI组)和γ-分泌酶抑制剂DAPT干预组(DAPT组)。分别于再灌注6 h、12 h、24 h、48 h、72 h时点观察各组肾脏病理改变,检测血尿素氮(BUN)和血清肌酐(Scr)水平,ELISA检测血清肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)水平,免疫组化和Western blot分别检测大鼠肾脏Notch1、TLR4和NF-κB p65蛋白表达水平。结果: 在IRI组,呈现不同程度的以肾小管上皮细胞和间质损伤为主的肾脏病理改变,BUN、Scr及血清炎性因子TNF-α、IL-6含量在各时点均显著高于sham组(P<0.05),而在DAPT干预组,在各时点肾脏病理损伤明显减轻,BUN、Scr和血清TNF-α、IL-6水平均显著低于IRI组(P<0.05)。Notch1、TLR4和NF-κB p65主要表达于肾小管上皮细胞胞质中,在sham组仅有微量表达,在IRI组则有高表达,在各时点表达与sham组相比均显著增强(P<0.05),而在DAPT组,各因子的表达水平在各时点均较IRI组显著降低(P<0.05)。结论: 大鼠肾脏IRI出现显著的肾功能及肾脏病理改变,血清炎性因子TNF-α和IL-6水平升高,Notch1、TLR4及NF-κB p65在肾组织中表达增强;而DAPT可通过抑制Notch1活化和TLR4/NF-κB通路,抑制TLR4所介导的炎症反应,从而发挥肾脏保护作用。

Role of Notch pathway in Toll-like receptor 4 mediated inflammatory response in renal ischemia reperfusion injury in rats

AIM: To investigate the role of the Notch pathway in Toll-like receptor 4(TLR4)-mediated inflammatory response in renal ischemia reperfusion injury(IRI) in rats. METHODS: A total of 75 male sprague-Dawley rats were randomly divided into sham operation group, IRI group and DAPT treatment group. Blood samples and the kidneys were obtained at 6 h, 12 h, 24 h, 48 h and 72 h after reperfusion. The concentrations of blood urea nitrogen(BUN) and serum creatinine(Scr) were measured. The serum levels of tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) were detected by ELISA, and the expression of Notch1, TLR4 and NF-κB p65 in the renal tissues was assessed by immunohistochemistry and Western blot. RESULTS: The serum levels of BUN, Scr, TNF-α and IL-6 in IRI group were markedly increased as compared with sham group(P<0.05). The protein levels of Notch1, TLR4 and NF-κB p65 in renal tubular epithelial cells in IRI group was significantly enhanced as compared with sham group(P<0.05). In DAPT group, the serum levels of BUN, Scr, TNF-α and IL-6 were significantly reduced compared with IRI group(P<0.05), and the protein levels of Notch1, TLR4 and NF-κB p65 were apparently less than those in IRI group(P<0.05). CONCLUSION: Significant changes of renal function, a rise of serum inflammatory factor including TNF-α and IL-6 and enhanced expression of Notch1, TLR4 and NF-κB p65 in the renal tissue occurred in the rats with IRI. γ-Secretase inhibitor DAPT attenuates TLR4-mediated inflammatory response in the renal IRI through the inhibition of Notch1 and down-regulation of NF-κB.