黏着斑激酶在2型糖尿病大鼠肾组织中的表达变化及意义

 目的：观察黏着斑激酶（FAK）在2型糖尿病（T2DM）大鼠肾组织中的动态变化，探讨其在糖尿病肾病（DN）发病机制中的作用。方法：复制T2DM模型，随机分为糖尿病8、12和16周(DM8、DM12和DM16)组，另设正常对照(NC)组和高脂高糖对照(HC)组。免疫组织化学检测肾组织中FAK、转化生长因子β1(TGF-β1)、细胞外信号调节激酶1/2(ERK1/2)、p-ERK1/2和纤维连接蛋白(FN)的表达；Western blotting检测FAK和p-FAK(Tyr397)蛋白水平；RT-PCR法检测肾皮质FAK mRNA的水平。结果：DM各组TGF-β1、p-ERK1/2和FN蛋白表达显著高于NC组及HC组(P<0.05)；DM12和DM16组肾皮质FAK和p-FAK (Tyr397)表达均较NC组、HC组及DM8组显著增多(P< 0.05)，且p-FAK(Tyr397)与总FAK蛋白表达趋势一致；FAK与TGF-β1、p-ERK1/2、FN呈显著正相关（P<0.01）。DM12和DM16组FAK mRNA比NC组、HC组及DM8周组表达明显增加(P< 0.05)。结论: 在2型糖尿病中，FAK可能作为TGF-β1的下游分子被活化，并通过活化ERK1/2使FN表达增多，从而参与了糖尿病肾病的发生发展。

Role of focal adhesion kinase expression in renal tissues of type 2 diabetic rats

AIM：To explore the dynamic change of focal adhesion kinase (FAK) in renal tissues of rats with type 2 diabetes mellitus (T2DM), and to investigate its role in the pathogenesis of diabetic nephropathy (DN). METHODS：The rat model of T2DM was established and the diabetic rats were randomly divided into 8-week DM (DM8), 12-week DM (DM12) and 16-week DM (DM16) groups. Meanwhile, normal control (NC) and high-fat high-sucrose control (HC) groups were also established. The protein expression of FAK, transforming growth factor β1 (TGF-β1), extracellular signal-regulated kinase 1/2 (ERK1/2), p-ERK1/2 and fibronectin (FN) was detected by immunohistochemical staining. The protein levels of FAK and p-FAK (Tyr397) were detected by Western blotting. The mRNA level of FAK in the renal cortex was examined by RT-PCR. RESULTS：The expression of FAK protein in renal tubular epithelial cells in DM12 and DM16 groups was significantly higher than that in NC, HC and DM8 groups (P<0.05). Moreover, TGF-β1, p-ERK1/2 and FN protein expression in DM groups was significantly increased compared with NC and HC groups (P<0.05). The levels of FAK and p-FAK (Tyr397) in the renal cortex in DM12 and DM16 groups were significantly up-regulated compared with NC, HC and DM8 groups (P<0.05), and the expression trend of p-FAK in different groups was in accordance with that of total FAK. The FAK protein expression was positively correlated with the expression of TGF-β1, p-ERK1/2 and FN proteins (P<0.01). Compared with NC, HC and DM8 groups, the expression of FAK mRNA increased remarkably in DM12 and DM16 groups (P<0.05). CONCLUSION: There is a possibility that FAK is activated as a downstream effector of TGF-β1 in T2DM, which enhances the expression of FN protein through activating ERK1/2, and therefore plays an important role in the pathogenesis of type 2 diabetic nephropathy.