脂多糖刺激的星形胶质细胞可能通过IL-6介导PC12细胞增殖双重性

目的：研究脂多糖（LPS）刺激的星形胶质细胞（AC）条件培养液（ACM）对PC12细胞生长的影响及其可能的因子。方法：在原代培养的AC中加入不同浓度的LPS作用24h，收集条件培养液，观察ACM对PC12细胞生长的影响，分析AC分泌的细胞因子的变化，研究IL-6中和抗体后处理的ACM对PC12细胞生长的影响。结果：ACM可促进PCI2细胞的增殖，0．1mg·mL^-1 LPS刺激组作用最强。LPS可促进AC分泌IL-6，并呈剂量依赖性。IL-6中和抗体可阻断这种效应。结论：AC对PC12的生长具有双重性，IL-6可能是关键的因素之一。

Astrocytes Administrated with LPS Had a Dual Effect on the Growth of PC12 by IL-6

Aim： To investigate the changes of growth of PC12 cells treated with astrocyte conditioned medium （ACM） which was dealt with LPS and the probable mechanisms. Methods. Firstly, the astrocyte conditioned medium （ACM） was obtained after astrocytes were administrated with LPS over 24 h. Secondly, the ACM was stratified by ultrafree MC filter units. Subsequently, the changes of the growth of PC12 cells cultivated with the ACM were detected by MTT method. The cytokines secreted by astrocytes after administration with LPS for 24 h were also studied. Finally, the effect Of the ACM pretreated with rabbit anti-rat IL-6 monoclone antibody on the growth of PC12 cells was observed. Results： ACM treated with LPS of low concentration could promote proliferation of PC 12 and increase the cell viability（P 〈 0.05 vs control）, while ACM treated with LPS of high concentration attenuated the proliferation of PC12. The ACM of molecular weight from 5 000 to 30 000 had the biggest effect on the proliferation of PC12. Being administrated for 24h, LPS could promote the astrocytes to secrete IL-6 in a concentration-dependent manner, while the secretions of GDNF, TNF-α, NO had no significant changes. Low concentration in LPS up-regulated the production of GSH and the activity of GPx, but high concentration down-regulated. Rabbit anti-rat IL-6 monoclone antibody could block the effect. Conclusion ： ACM treated with LPS of low concentration could promote the effects of astrocytes on proliferation of PC 12 cells while high concentration not. The dual effect might be related to IL-6.