糖尿病肾病模型中UCH-L1蛋白表达变化的研究

Expression changes in UCH-L1 protein in diabetic nephropathy model

目的研究泛素羧基末端水解酶L1(UCH-L1)蛋白在糖尿病肾病(DN)模型中的表达变化。方法原代培养大鼠肾小球系膜细胞,分别给予30mmol/L葡萄糖(高糖组)、5.4mmol/L葡萄糖(正常对照组),在0、8、16、72h采用MTT法动态观察两组细胞增殖情况,Western boltting检测UCH-L1蛋白表达情况。采用自发性2型DN模型OLETF大鼠,每4周一次动态监测血糖及24h尿蛋白定量,于36周时处死大鼠,观察肾组织病理改变并采用Western boltting分析肾皮质中UCH-L1的表达。结果高糖环境能抑制大鼠肾小球系膜细胞的增殖。与正常对照组相比,高糖组系膜细胞UCH-L1蛋白表达在8、72h时点明显降低,16h时点明显增高,差异有统计学意义(P<0.01)。与对照LETO大鼠相比,OLETF大鼠血糖、24h尿蛋白定量均逐渐增高,36周时肾脏发生了DN的早期病理改变,且肾皮质中UCH-L1蛋白表达降低(P<0.01)。结论 UCH-L1蛋白表达在DN模型中以降低为主。蛋白降解途径失调可能在DN的发生、发展起到一定作用。

Objective To investigate the expression changes in ubiquitin carboxy-hydrase L1 （UCH-L1） protein in diabetic nephropathy （DN） model. Methods The primarily cultured glomerular mesangial cells of rats were treated with S.4mmol/L of glucose （normal control group） or 30mmol/L of glucose （high glucose group）, and then cultured for 0, 8, 16 and 72 hours. The proliferation of mesangial cells in both groups were assayed by MTTj and the expression of UCH-L1 protein was detected by Western blotting at aforementioned 4 time-points. Spontaneous type 2 DN model OLETF and its normal control LETO rats were imported from Japan, and their serum glucose and 24h total urinary protein （TUP） were dynamically monitored every 4 weeks. The model rats were sacrificed at the 36th week, their pathological changes in nephridial tissue were surveyed, and the expression level of UCH-L1 in the cortex of kidney was analyzed by Western blotting. Results High glucose may inhibit the proliferation of rat mesangial cells. The expression level of UCH-L1 in mesangial cells was reduced at the time-points 8 and 72 hours, and elevated obviously at 16 hours in high glucose group, when compared with that in normal control group （P〈0.01）. The level of serum glucose and 24h TUP increased gradually in OLETF rats as compared with that in LETO rats. The early pathological changes of DN were observed in the nephridial tissue of OLETF rats sacrificed at the 36th week, and the expression of HCH-L1 in the cortex of kidney was reduced in OLETF rats compared with that in LETO rats. Conclusion A reduction of HCH-L1 protein expression exists in most of the DN models, implying that the dysfunction of protein degradation may play a certain role in the pathogenesis and development of DN.