霉酚酸酯对小鼠肾脏缺血再灌注损伤早期单核细胞TLR4信号传导途径的影响

Mycophenolate mofetil affects Toll-like receptor 4 signaling pathway of monocytes in renal ischemia/reperfusion injury(IRI) of mice

目的探讨在小鼠肾脏缺血再灌注免疫损伤早期过程中霉酚酸酯对单核细胞TLR4信号传导途径的影响。方法采用雄性Bal B/C小鼠,随机分为2组。肾脏缺血再灌注损伤(IRI)组:采用双肾蒂阻断,缺血时间为45 min,分别于6 h、12 h、24 h、48 h再灌注。每个时间点6只小鼠;霉酚酸酯(MMF)药物组:缺血前2 d开始灌胃给MMF 40 mg?kg-1?d-1,其余同肾脏缺血再灌注损伤组。两组均设假手术对照各6只;观察不同时间点各组动物肾功能、肾组织学变化;流式细胞学检测单核细胞表面TLR4的表达及CBA法检测血浆细胞因子(IL-6、MCP-1、TNF-α)浓度;ELISA法检测血浆中TLR4配体HMGB-1的浓度。结果 MMF组较IRI组血肌酐水平明显降低(再灌注6 h、12 h、24 h、48 h,均P<0.05),病理组织学观察提示MMF组肾脏损伤程度较轻;而血浆中TLR4配体HMGB-1浓度无显著性差异(P>0.05),单核细胞表面TLR4表达及血浆细胞因子(IL-6、MCP-1、TNF-α)浓度均明显降低(P<0.05)。结论霉酚酸酯可减轻小鼠肾脏缺血再灌注损伤后肾功能和肾组织的损伤,可抑制小鼠肾脏缺血再灌注损伤早期过程中单核细胞TLR4信号转导途径的活化。提示单核细胞TLR4信号转导途径在小鼠肾脏缺血再灌注损伤早期过程中起着重要的调控作用,而霉酚酸酯可以通过抑制该途径对肾脏起到保护作用。

Objective The objective was to research the effect of Mycophenolate mofetil （MMF） on Toll-like receptor 4 （TLR4） signaling pathway of monocytes in the early stage of renal ischemia/reperfusion injury （IRI） of mice. Methods Male BalB/C mice were divided to 3 groups randomly, 6 mice were given sham surgery, group IRI received renal IRI, renal pedicles were clamped for 45 minutes using microaneurysm clamps through a midline abdominal incision under general anesthesia, group MMF was given MMF （40 mg？kg-1？d-1, i. p.） from 2 days before renal IRI. After surgery, the plasm creatinine, renal tissue damage of all the mice were observed at different times. The concentration of cytokines （IL-4, IL-6, IL-10, IFN-γ, TNF-α） in plasma and the expression of TLR4 on monocytes were determined with flow cytometry. The concentration of HMGB-1 （high motility group box protein 1, ligand of TLR4） in plasma were determined with ELISA. Results Compared to group IRI, The concentration of creatinine in plasma of group MMF were obviously lower （after reperfusion of 6 h, 12 h, 24 h or 48 h, P〈0.05）, the pathology results showed that the renal damage was slighter, the expression of TLR4 of group IRI was obviously less（after reperfusion of 6 h, 12 h, 24 h or 48 h, P〈0.05） and the concentration of IL-4,IL-6, IL-10, IFN-γand TNF-α（especially the IFN-γand TNF-α） in plasma was obviously lower （P〈0.05）. There was no difference in the concentrations of HMGB-1 between group IRI and group MMF （P〉0.05）. Conclusion MMF can inhibit the TLR4 signaling pathway of monocytes in the early stage of renal ischemia/reperfusion injury of mice, and so can improve the renal function.