泛素蛋白酶体途径对高糖刺激肾系膜细胞连接蛋白43表达和纤维连接蛋白分泌影响的初步观察

Effect of ubiquitin-proteasome pathway on the expression of connexin 43 and secretion of fibronectin in mesangial cells induced by high glucose

目的探讨高糖对系膜细胞连接蛋白43(Cx43)表达和纤维连接蛋白(FN)分泌的影响,以及泛素蛋白酶体途径在其中的作用。方法将培养的大鼠肾小球系膜细胞用高糖作为刺激因子,泛素蛋白酶体特异性抑制剂MG132作为阻断剂,甘露醇作为渗透压对照,观察各组细胞间Cx43的表达并检测细胞上清液中FN的含量。结果 (1)不同浓度的葡萄糖刺激系膜细胞48h后,Cx43表达较正常对照组显著降低,MG132可部分逆转高糖所致的Cx43的低表达(P<0.05),甘露醇对Cx43表达无影响(P>0.05)。(2)高糖呈浓度依赖性促进系膜细胞FN的分泌,MG132可部分抑制高糖所致的系膜细胞FN的分泌(P均<0.05)。结论高糖呈浓度依赖性抑制系膜细胞Cx43的表达和促进FN的分泌;泛素蛋白酶体途径参与了高糖所致Cx43的低表达和FN分泌。

Objective To investigate the expression of connexin 43 （Cx43） and secretion of fihroneetin in rat glomerular mesangial cells exposed to high glucose and to explore the role of ubiquitin- proteasome pathway on the expression of Cx43 and secretion of fibronectin. Methods Cultured HBZY-1 mesangial cells were treated with different high glucose （10 - 30 mmol/L） and ubiquitin-proteasome inhibitor MG132 for 48 hours. The expression of Cx43 was measured by laser scanning eonfocal microscopy. The content of fibroneetion in GMC culture supernate was assessed by ELISA. Results 1. Compared with control group,the expression of Cx43 was decreased when exposed to high glucose in a concentration-dependent manner（P〈0. 05）. After adding MG132, the expression of Cx43 was increased while compared with 30mmol/L glucose group （P〈0. 05）. 2. The content of fibroneetion in GMC when exposed to high glucose was increased as compared with controls in a dose-dependent manner. MG132 can inhibit these ehange（P〈0. 05）. Conclusions High glucose decreases the Cx43 expression and increases the secretion of fibronection in a dose-dependent manner by ubiquitin-proteasome pathway.