高糖对肾小管上皮细胞内质网应激的影响及冬虫夏草的干预作用

目的：观察高糖对肾小管上皮细胞凋亡和内质网应激标志物表达的影响，研究冬虫夏草提取液对高糖诱导的肾小管上皮细胞内质网应激的可能保护机制。方法：体外培养大鼠肾小管上皮细胞，分为正常低糖组、低糖+冬虫夏草组、高渗组、高渗+冬虫夏草组、高糖组、高糖+冬虫夏草组和高糖+高渗+冬虫夏草组，用Realtime-PCR法检测各组细胞葡萄糖调解蛋白78（Grp78）、半胱氨酸蛋白酶蛋白12（caspase-12）及I型胶原mRNA的表达，采用酶联免疫吸附法测定细胞上清液中I型胶原的分泌，Western-blotting检测Grp78及caspase-12蛋白表达。结果：高糖组与低糖组相比，Grp78、Caspase-12及Ⅰ型胶原mRNA和蛋白水平明显上升，差异均有统计学意义（P<0.05）；低糖+冬虫夏草组、高渗组及高渗+冬虫夏草组与低糖组相比，Grp78、Caspase-12 mRNA及Ⅰ型胶原mRNA和蛋白水平无明显差别（P>0.05）；与高糖组相比，高糖+冬虫夏草干预组Grp78、Caspase-12及Ⅰ型胶原mRNA和蛋白表达下降，差异均有统计学意义（P<0.05）。结论：冬虫夏草对高糖诱导下肾小管上皮细胞凋亡及肾脏纤维化具有一定抑制作用，其机制可能与抑制内质网应激反应有关。

Effects of high glucose on endoplasmic reticulum stress of renal tubular epithelial cells and protective effects of Cordyceps sinensis

OBJECTIVE To investigate the role of high glucose on endoplasmic reticulum stress in renal tubular epithelial cells and apoptosis of cells,and protective effects of Cordyceps sinensis on endoplasmic reticulum stress of renal tubular epithelial cells induced by high glucose.METHODS Rat renal tubular epithelial cells were incubated and divided into groups including normal low glucose group,normal low glucose+Cordyceps sinensis group,hypertonic control group,hypertonic+Cordyceps sinensis group,high glucose group,high glucose+Cordyceps sinensis group,high glucose+hypertonic+Cordyceps sinensis group.The mRNA expressions of glucose-regulated protein 78 (Grp78) and cysteme aspartate specific protease-12 (caspase-12) were detected by real time PCR.Protein expression of Collagen I was detected by enzyme-linked immunosorbent assay.Protein expressions of Grp78 and caspase-12 were detected by Western blotting.RESULTS Levels of mRNA and protein of Grp78,Caspase-12 and Collagen I in high glucose group were significantly higher than those in normal low glucose group (P<0.05).Compared with normal low glucose group,mRNA and protein of Grp78,Caspase-12 and Collagen I in normal low glucose+Cordyceps sinensis group,hypertonic control group,hypertonic+Cordyceps sinensis group were not significantly changed (P>0.05).Levels of mRNA and protein of Grp78,Caspase-12 and Collagen I in Cordyceps sinensis group were significantly lower than those of high glucose group (P<0.05).CONCLUSION Cordyceps sinensis can suppress apoptosis and fibrosis of tubular epithelial cells induced by high glucose,and protective effects of Cordyceps sinensis may inhibit the endoplasmic reticulum stress.