雷帕霉素对糖尿病肾病大鼠足细胞生物学行为及mTOR信号通路的影响

为了探究雷帕霉素对糖尿病肾病大鼠足细胞生物学行为及哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin，mTOR）信号通路的影响，采用链脲霉素腹腔注射构建糖尿病肾病大鼠模型，将正常大鼠体内取出的足细胞设为对照组，模型大鼠体内取出的足细胞设为糖尿病肾病模型组（DN组），取2 mg·kg^-1雷帕霉素干预DN组足细胞，并将其设为雷帕霉素组（RAPA组）。采用3-（4，5-二甲基噻唑-2）-2，5-二苯基四氮唑溴盐3-（4，5-dimethylthiahiazo-z-y1）-2，5-diphenytetrazoliumromide，MTT]法检测足细胞增殖水平，Transwell检测细胞迁移和侵袭能力，流式细胞术检测细胞凋亡水平，Western blot法检测上皮-间充质转化标志物E-钙黏蛋白（E-cadherin）、N-钙黏蛋白（N-cadherin）、波形纤维蛋白（vimentin）]、mTOR和核糖体S6激酶1（S6K1）蛋白表达水平。结果显示，与对照组相比，DN组细胞增殖水平显著被抑制，细胞迁移、侵袭水平显著升高，细胞凋亡率显著增加，上皮-间充转标志物E-cadherin表达显著下调，N-cadherin和Vimentin表达显著上调，mTOR/S6K1信号通路被显著活化（P<0.05）。与DN组相比，RAPA组细胞增殖水平显著升高，细胞迁移、侵袭水平显著降低，细胞凋亡率显著降低，E-cadherin表达显著上调，N-cadherin和Vimentin表达显著下调，mTOR和S6K1的蛋白表达显著被抑制（P<0.05）。结果表明，雷帕霉素通过抑制mTOR信号通路，促进足细胞体外增殖，抑制细胞迁移、侵袭、凋亡和上皮-间充质转化，发挥对糖尿病肾病大鼠足细胞的保护作用。

Effects of Rapamycin on the Biological Behaviors of Podocytes and mTOR Signaling Pathway in Rats with Diabetic Nephropathy

To explore the effects of rapamycin on the biological behaviors of podocytes and mammalian target of rapamycin （mTOR） signaling pathway in rats with diabetic nephropathy， streptozotocin was injected intraperitoneally to construct a rat model of diabetic nephropathy. The podocytes taken from normal rats were set as control group， and the podocytes taken from the model rats were enrolled as diabetic nephropathy model group （DN）. The podocytes taken from DN group were intervened with 2 mg·kg^-1 rapamycin and selected as rapamycin group （RAPA）. 3-（4， 5-dimethylthiahiazo-z-y1）-2， 5-diphenytetrazoliumromide （MTT） was used to detect podocyte proliferation level， and Transwell was used for detection of cell migration and invasion and flow cytometry for cell apoptosis level. Western blot was adopted to measure the protein expression levels of epithelial-mesenchymal transition markers （E-cadherin， N-cadherin， vimentin）， mTOR and ribosomal protein S6 kinase 1 （S6K1）. The results showed that， compared to the control group， the cell proliferation level was significantly inhibited， the cell migration and invasion were significantly increased， the apoptosis rate was significantly enhanced， the expression of epithelial-mesenchymal transition marker E-cadherin was significantly down-regulated while the expressions of N-cadherin and Vimentin were significantly up-regulated， the mTOR/S6K1 signaling pathways were significantly activated in the DN group（P<0.05）. Compared to the DN group， the cell proliferation level was significantly increased， the cell migration and invasion in the RAPA group were significantly reduced， the apoptosis rate was significantly reduced， the expression of E-cadherin was significantly up-regulated while the expressions of N-cadherin and Vimentin were significantly down-regulated， the protein expressions of mTOR and S6K1 were significantly inhibited in the RAPA group （P<0.05）. The results indicated that rapamycin could promote the proliferation of podocytes in vitro and inhibit the cell migration， invasion， apoptosis and epithelial-mesenchymal transition by inhibiting the mTOR signaling pathway， and it exerts a protective effect on podocytes in rats with diabetic nephropathy.