目的 探讨二甲双胍对高糖诱导的肾小管上皮HK-2细胞上皮间质转化（EMT）的影响及其机制。方法 以0、7.5、15.0、30.0、60.0、120.0 mmol/L二甲双胍作用48 h后，采用噻唑蓝（MTT）法检测HK-2细胞活力以筛选合适的二甲双胍作用浓度；将体外培养的HK-2细胞分为对照组（5.5 mmol/L D-葡萄糖）、高渗组（24.5 mmol/L甘露醇和5.5 mmol/L D-葡萄糖）、高糖组（30 mmol/L D-葡萄糖）、高糖+7.5 mmol/L二甲双胍组（30 mmol/L D-葡萄糖+7.5 mmol/L二甲双胍）和高糖+15 mmol/L二甲双胍组（30 mmol/L D-葡萄糖+15 mmol/L二甲双胍），倒置显微镜观察各组HK-2细胞形态，免疫印迹法（Western blotting）检测各组HK-2细胞中α-平滑肌肌动蛋白（α-SMA）、E-钙黏附蛋白（E-cadherin）、转化生长因子-β（TGF-β）、细胞外信号调节激酶（ERK）、磷酸化（p）-ERK、基质金属蛋白酶9（MMP-9）蛋白表达水平，实时荧光定量PCR（qRT-PCR）检测α-SMA、E-cadherin、TGF-β、ERK、MMP-9 mRNA表达水平。结果 与对照组相比，30.0、60.0 mmol/L二甲双胍作用后HK-2细胞活力明显升高，120.0 mmol/L二甲双胍作用后HK-2细胞活力明显降低（P<0.05），而7.5、15.0 mmol/L二甲双胍作用后HK-2细胞活力差异无统计学意义（P>0.05）；与对照组比较，高渗组细胞形态无明显改变，且细胞中α-SMA、E-cadherin、TGF-β、MMP-9蛋白和mRNA表达水平以及p-ERK/ERK蛋白、ERK mRNA表达水平差异均无统计学意义（P>0.05），但高糖组细胞失去原有形态变为长梭形，且细胞中α-SMA、TGF-β蛋白和mRNA表达水平以及p-ERK/ERK蛋白、ERK mRNA表达水平明显升高，而MMP-9、E-cadherin蛋白和mRNA表达水平明显降低（P<0.05）；与高糖组比较，高糖+7.5 mmol/L二甲双胍组、高糖+15.0 mmol/L二甲双胍组细胞形态由长梭形逐渐变成圆形或椭圆形，且α-SMA、TGF-β蛋白和mRNA表达水平以及p-ERK/ERK蛋白、ERK mRNA表达水平明显降低，而MMP-9、E-cadherin蛋白和mRNA表达水平明显升高（P<0.05），且高糖+15.0 mmol/L二甲双胍组细胞上述指标变化幅度大于高糖+7.5 mmol/L二甲双胍组。结论 二甲双胍可抑制高糖诱导的肾小管上皮HK-2细胞EMT，其作用机制可能与抑制TGF-β/ERK/MMP-9通路活化有关。

Objective To investigate the effect of metformin on high glucose-induced epithelial mesenchymal transition (EMT) in HK-2 cells in renal tubular epithelium. Methods After treated with 0, 7.5, 15.0, 30.0, 60.0 and 120.0 mmol/L metformin for 48 h, the viability of HK-2 cells was detected by MTT method to select the appropriate concentration of metformin. HK-2 cells cultured in vitro were divided into control group (5.5 mmol/L D-glucose), hypertonic group (24.5 mmol/L mannitol and 5.5 mmol/L D-glucose), high glucose group (30 mmol/L D-glucose), high glucose + 7.5 mmol/L metformin group (30 mmol/L D-glucose + 7.5 mmol/L metformin) and high glucose + 15.0 mmol/L metformin group (30 mmol/L D-glucose + 15.0 mmol/L metformin). The morphology of HK-2 cells was observed under inverted microscope. Western blotting method was used to detect the protein expression levels of α-smooth muscle actin (α-SMA), E-cadherin, transforming growth factor-β (TGF-β), extracellular signal regulated kinase (ERK), phosphorylation (p)-ERK and matrix metalloproteinase-9 (MMP-9) in HK-2 cells, and real time fluorescent quantitative PCR (qRT-PCR) was used to detect the mRNA expression levels of α-SMA, E-cadherin, TGF-β, ERK and MMP-9. Results Compared with 0 mmol/L, 30 and 60 mmol/L metformin increased the viability of HK-2 cells significantly. After treated with 120.0 mmol/L metformin, the viability of HK-2 cells decreased significantly (P<0.05). Compared with those in the control group, there was no significant difference in HK-2 cell viability between the treat of 7.5 mmol/L and 15.0 mmol/L metformin (P>0.05). Compared with those in the control group, there was no significant change in cell morphology in the hypertonic group, the expression levels of α-SMA, E-cadherin, TGF-β and MMP-9 protein and mRNA, and p-ERK/ERK protein and ERK mRNA were not significantly different (P>0.05). However, the cells in high glucose group lost their original shape and became long spindle shape, the expression levels of α-SMA and TGF-β protein and mRNA, p-ERK/ERK protein and ERK mRNA were significantly higher, and the expression levels of MMP-9 and E-cadherin protein and mRNA were significantly lower (P<0.05). Compared with those in high glucose group, the morphology of cells in high glucose + 7.5 mmol/L metformin group and high glucose + 15.0 mmol/L metformin group gradually changed from long spindle shape to round or oval shape, the expression levels of α-SMA and TGF-β protein and mRNA, p-ERK/ERK protein and ERK mRNA were significantly lower, the expression levels of MMP-9 and E-cadherin protein and mRNA were significantly higher (P<0.05). The changes of the above indexes in high glucose + 15.0 mmol/L metformin group were greater than those in high glucose + 7.5 mmol/L metformin group. Conclusion Metformin can inhibit high glucose-induced EMT in HK-2 cells in renal tubular epithelium, which may be related to the inhibition of TGF-β/ERK/MMP-9 pathway activation.

R966

河南省医学科技攻关计划项目（2018020300）