LPS活化的小胶质细胞对人脐静脉内皮细胞VEGF及ZO-1表达的影响

目的研究活化的小胶质细胞对人脐静脉内皮细胞（human umbilical vein endothelial cells，HUVECs）血管内皮生长因子（vascular endothelial growth factor，VEGF）和ZO-1表达的影响。方法原代培养视网膜小胶质细胞，纯化鉴定后分为三组：A组，空白对照组；B组，未激活的小胶质细胞组；C组，100ng／mL脂多糖（lipopolysaccharide，LPS）激活的小胶质细胞组，然后采用Transwell小室与HUVECs共培养。用免疫荧光染色观察各组HUVECs紧密连接蛋白ZO-1的表达，并用Western Blot方法检测各组细胞VEGF和ZO-1的表达。结果细胞免疫荧光染色结果显示，LPS活化的小胶质细胞作用于HUVECs后，HUVECs的ZO-1表达明显低于未活化的小胶质细胞作用组和空白对照组。Western Blot结果亦显示，LPS活化的小胶质细胞作用组ZO-1的表达明显低于未活化的小胶质细胞作用组和空白对照组（P〈0．05），而VEGF表达则高于未活化的小胶质细胞作用组和空白对照组（P〈0．05）。结论活化的小胶质细胞影响血管内皮细胞表达VEGF和ZO-1，可能是导致屏障功能破坏的重要机制之一。

Effects of lipopolysaccharide-activated retinal microglia on the expression of vascular endothelial growth factor and ZO-1 in human umbilical vein endothelial cells

Objective To investigate the effect of lipopolysaccharide （LPS）-activated retinal microglia on the expression of vasular endothelial growth factor （VEGF） and ZO-1 in human umbilical vein endothelial cells （HUVECs）. Methods Retinal microglia were isolated from newborn Sprague-Dawley （SD） rats. Cultured retinal microglia were collected and cultured onto Transwell permeable support membrane inserts, then activated by the addition of LPS. The previously prepared Transwell inserts containing either untreated or LPS-treated retinal microglia were then placed into wells with HUVECs. Control cultures were incubated with empty inserts without cultured mlcroglia. Immunocytochemistry was applied to observe ZO-1 expression in these HUVECs. The expression of VEGF and ZO-1 was detected by Western blot. Results HUVECs co-cultured with LPS-treated retinal microglia, compared to either untreated or unexposed HUVECs, expressed lower levels of ZO-1 （ P 〈 0.05 ）. Western Blot analysis revealed an upregulation of VEGF and a downregulation of ZO-1 in HUVECs which was co-cultured with LPS-treated retinal microglia（ P 〈 0.05 ）. Conclusions Activated microglia could affect the expression of VEGF and ZO-1, and might play an important role in barrier breakdown.