MyD88抑制肽对小鼠脑缺血后小胶质细胞极化的影响

Effects of MyD88 inhibitory peptide on microglia polarization after cerebral ischemia in mice

目的:研究髓样分化因子88抑制肽(MIP)对小鼠脑缺血后小胶质细胞极化的影响。方法:将30只雄性C57BL/6小鼠分为假手术组(sham)、局灶性脑缺血组(FCI)和给药组(MIP)。用光化学法建立小鼠FCI模型,给药组于造模后第3 d开始给予腹腔注射MIP,每次10 mg/kg,每日一次,连续3 d。采用real time RT-PCR检测损伤区白细胞介素(IL)-1β、IL-4、IL-10、肿瘤坏死因子α(TNF-α)、CD86和CD206 mRNA的表达,用Western Blot检测损伤区局部Toll样受体2(TLR2)、TLR4、髓样分化因子88(MyD88)、诱导型一氧化氮合酶(iNOS)和精氨酸酶-1(Arg-1)蛋白的表达水平,用免疫荧光染色观察损伤区i NOS和Arg-1与F4/80或Iba-1的共标情况。结果:与假手术组相比,FCI组小鼠损伤区MyD88、TLR2和TLR4蛋白的表达水平明显升高。与FCI组相比,MIP给药组小鼠损伤区IL-1β、TNF-α和CD86 mRNA,以及iNOS蛋白的表达量明显下降,而IL-4、IL-10和CD206 mRNA,以及Arg-1蛋白的表达量明显上调。结论:MIP可促使脑缺血模型小鼠损伤区小胶质细胞向M2方向极化。

Objective: To investigate the effects of myelin differentiation factor 88 inhibitory peptide(MIP) on microglia polarization after cerebral ischemia in mice.Methods: 30 male C57 BL/6 mice were divided into sham group(sham),focal cerebral ischemia model group(FCI),and MIP treatment group(MIP).FCI model mice were prepared by photochemical methods.MIP group mice were given intraperitoneal injection of MIP at 10 mg/kg once a day for 3 days.The expressions of interleukin(IL)-1β,IL-4,IL-10,tumor necrosis factor α(TNF-α),CD86,and CD206 mRNA in the damaged area were detected by real time RT-PCR.The expressions of myelin differentiation factor 88(MyD88),toll-like receptor(TLR) 2,TLR4,inducible nitric oxide synthase(i NOS),and arginase-1(Arg-1) in the lesion were detected by Western Blot.The co-labeling of i NOS and Arg-1 with F4/80 or Iba-1 was observed by immunofluorescence staining.Results: Compared with the sham group,the expression levels of MyD88,TLR2,and TLR4 proteins in the damaged area of FCI group were obviously increased.Compared with the FCI group,the expression levels of IL-1β mRNA,TNF-ɑ mRNA,CD86 mRNA and iNOS protein in the lesion of MIP group were distinctly decreased,while the expression levels of IL-4 mRNA,IL-10 mRNA,CD206 mRNA and Arg-1 protein were significantly increased.Conclusion: MIP may induce microglia to M2 phenotype polarization in the damaged area after cerebral ischemia model of mice.