论文部分内容阅读
目的探讨脂多糖(LPS)诱导小胶质细胞(MG)激活导致少突胶质细胞(OL)前体死亡的信号转导通路及LPS诱导MG激活的跨膜转导机制。方法取2日龄Toll样受体4(TLR4)基因缺失小鼠和野型小鼠脑内MG和OL前体共培养,分别分为共培养对照组和共培养LPS组。经LPS100 mg.L-1诱导48 h后,各组共培养细胞,应用硝酸还原酶-比色法检测其一氧化氮(NO)水平、还原-比色法检测其超氧阴离子(O2-)水平,免疫荧光染色法检测其过氧亚硝酸盐(ONOO-)水平,Hochest33342/碘化丙啶荧光染色法观察细胞死亡的形态学改变,流式细胞仪检测其细胞凋亡率。结果 LPS诱导引起野型小鼠共培养细胞内NO和ONOO-水平显著增加,OL前体坏死和凋亡率明显增高。但LPS诱导对TLR4基因缺失小鼠共培养细胞内NO和ONOO-水平以及OL前体坏死及凋亡率均无明显影响。2种小鼠共培养细胞内O2-水平在LPS的诱导下均显著提高。结论 LPS诱导MG激活的跨膜转导机制以及导致OL前体死亡的信号转导通路,必须依赖TLR4的介导。LPS诱导共培养细胞内O2-水平增加可能通过其他非TLR4受体依赖途径。
Objective To investigate the signal transduction pathway of lipopolysaccharide (LPS) -induced microglia (MG) activation leading to the death of oligodendrocyte (OL) precursors and the transmembrane transduction mechanism of LPS-induced MG activation. Methods Two-day-old Toll-like receptor 4 (TLR4) gene-deficient mice and wild-type mice were co-cultured with MG and OL precursors and divided into co-cultured control group and co-cultured LPS group, respectively. After induced by LPS100 mg.L-1 for 48 h, the cells were co-cultured and the level of nitric oxide (NO) was detected by nitrate reductase-colorimetry. The superoxide anion (O2-) The levels of peroxynitrite (ONOO-) were detected by immunofluorescence staining. The morphological changes of cell death were observed by Hochest33342 / propidium iodide staining. The apoptosis rate was detected by flow cytometry. Results LPS induced a significant increase of NO and ONOO- in co-cultured cells of wild type mice, and the rate of necrosis and apoptosis in OL precursors was significantly increased. However, LPS-induced TLR4 gene-deficient mice co-cultured with intracellular NO and ONOO- levels and OL precursor necrosis and apoptosis rate had no significant effect. The O2- levels of cocultured cells in both groups were significantly increased under the induction of LPS. Conclusion The transmembrane transduction mechanism induced by LPS and the signal transduction pathway leading to the death of OL precursor must be mediated by TLR4. LPS-induced increase in intracellular O2- levels in co-cultured cells may be via other non-TLR4 receptor-dependent pathways.