高糖对大鼠肾系膜细胞泛素及泛素化蛋白表达的影响

Impact of high glucose on the expression of ubiquitin mRNA and ubiquitinated-protein in cultured rat glomerular mesangiai cells

目的探讨高糖对大鼠肾系膜细胞泛素及泛素化蛋白表达的影响。方法将大鼠HBZY—1肾系膜细胞进行体外培养，高糖作为刺激因子，分别设正常对照组（5．6mmol／L葡萄糖）、高糖组（10、20、30mmol／L葡萄糖）、甘露醇组。刺激12、24、48h后，分别用实时定量PCR法和Western印迹法检测各组系膜细胞泛素mRNA和泛素化蛋白的表达。结果泛素化蛋白多以大分子蛋白为主。与正常对照组比较，30mmol／L葡萄糖刺激24h和48h后泛素化蛋白的表达分别增加36％和52％（均P〈0．01）；20mmol／L和30mmol／L葡萄糖作用48h泛素化蛋白的表达分别增加31％和52％（均P〈0．01）；高糖作用24、48h，泛素mRNA的表达显著增加（均P〈0．05）。结论高糖呈时间浓度依赖性地促进大鼠肾系膜细胞泛素mRNA及泛素化蛋白的表达，增加泛素蛋白酶体途径活性。

Objective To explore the impact of high glucose on the expression of ubiquitin mRNA and ubiquitinated-protein in cultured rat glomerular mesangial cells （GMCs）. Methods Cultured HBZY-1 rat GMCs were divided into 5 groups： normal glucose group （5.6 mmol/L）, high glucose group （10, 20, 30 mmol/L）. Mannitol group was used as high osmosis control. The expression of ubiquitinated-protein and ubiquitin mRNA of each group was measured by Western blot and real-time PCR respectively. Results Ubiquitinated-protein was mostly macromolecule. Compared with normal glucose group, the expression of ubiquitinated-protein was increased significantly in a dose- and time-dependent manner in 20,30 mmol/L glucose groups （all P〈O.O1）, and the expression of ubiquitin mRNA was also increased obviously （P〈0.05）. Conclusions High glucose can obviously increase the expression of ubiquitinated-protein and ubiquitin mRNA, and upregulate ubiquitin-proteasome pathway in cultured GMCs.