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目的探讨晚期糖基化终末产物(Advanced glycosylation end products,AGEs)对大鼠肾小管上皮细胞NRK-52E组织型转谷氨酰胺酶(Tissue transglutanunase,tTG)mRNA表达及其对细胞外基质(Extracellular matrix,ECM)降解的影响。方法体外培养NRK-52E细胞,分别用体外合成的不同浓度的糖化牛血清白蛋白(AGE-BSA)及未经糖化的牛血清白蛋白(BSA)处理48h,ELISA法检测细胞培养上清中纤维连接蛋白(Fibronectin,FN)和Ⅳ型胶原蛋白(TypeⅣcollagen,ColⅣ)含量,RT-PCR检测细胞tTG mRNA的表达。结果与BSA组比较,50～200mg/LAGE-BSA组细胞上清中FN含量明显增加(P<0.01),25～100mg/L AGE-BSA组细胞上清中ColⅣ含量明显增加(P<0.05);AGE-BSA(50～400mg/L)可不同程度地刺激细胞tTG mRNA表达的增加(P<0.05);tTG mRNA表达增加与FN、ColⅣ分泌增多呈正相关(r值分别为0.911和0.872)。结论 AGEs能诱导大鼠近端肾小管上皮细胞tTG mRNA的表达,引起ECM主要成分FN和ColⅣ含量增加,提示tTG可能在AGEs引起的ECM积聚过程中,起到抑制ECM蛋白降解的作用,进而参与糖尿病肾病的病理过程。
Objective To investigate the effect of advanced glycosylation end products (AGEs) on the expression of tissue transglutanase (tTG) mRNA in rat renal tubular epithelial cells (NRK-52E) and its effect on extracellular matrix matrix, ECM) degradation. Methods NRK-52E cells were cultured in vitro and treated with different concentrations of glycosylated bovine serum albumin (AGE-BSA) and non-glycosylated bovine serum albumin (BSA) in vitro for 48 h, respectively. Fibronectin (FN) and type Ⅳ collagen (Col Ⅳ) were detected by flow cytometry. The expression of tTG mRNA was detected by RT-PCR. Results Compared with BSA group, the content of FN in the supernatant of 50 ~ 200mg / L AGE-BSA group was significantly increased (P <0.01), but the level of ColⅣ in the supernatant of 25 ~ 100mg / ; AGE-BSA (50-400mg / L) could stimulate the increase of tTG mRNA expression (P <0.05). The increase of tTG mRNA expression was positively correlated with the increase of FN and ColⅣ (r = 0.911 and 0.872, respectively). Conclusion AGEs can induce the expression of tTG mRNA in proximal tubular epithelial cells of rats and lead to the increase of the content of FN and ColⅣ in ECM, suggesting that tTG might inhibit the degradation of ECM during ECM accumulation induced by AGEs, Diabetic nephropathy pathological process.