结缔组织生长因子在转化生长因子β诱导的肾小管上皮细胞转分化中的作用

目的：探讨结缔组织生长因子（CTGF）在转化生长因子-β1（TGF-β1）诱导的肾小管上皮细胞表型转化中的可能作用。方法： 将NRK52E肾小管上皮细胞分组处理，光镜、扫描电镜、透射电镜观察细胞形态的改变，细胞免疫组化检测ɑ-平滑肌肌动蛋白（α-SMA）和细胞角蛋白-18的表达，RT-PCR和Western blot检测Ⅰ型胶原的表达。 结果：TGF-β1 10 μg/L作用3 d，NRK52E小管上皮细胞失去正常的椭圆形，变得肥大，胞体拉长，扫描电镜下，见成纤维细胞状，失去上皮细胞特有的顶端-基底极性和表面的微绒毛结构，透射电镜下胞浆中见到微丝和致密体结构，骨架标志上肾小管上皮细胞较具特征性的细胞角蛋白-18表达减少,肌成纤维细胞标志性的α-SMA表达增多，Ⅰ型胶原分泌增多；加入TGF-β1中和抗体和CTGF反义寡核苷酸可以大部分阻断TGF-β的作用，而正义的CTGF寡核苷酸不能阻断TGF-β的作用。 结论： NRK52E细胞中，CTGF作为TGF-β的下游效应因子，介导了TGF-β诱导的肾小管上皮细胞转分化。

Role of connective tissue growth factor in the transdifferentiation of renal epithelial cells induced by transforming growth factor- β

AIM: To investigate the role of connective tissue growth factor (cTGF) in transforming growth factor-β-induced tubular-epithelial myofibroblasts trnansdifferentiation. METHODS: NRK52E cells were used and divided into several groups. The morphological changes were observed by light and electron microscopy (scanning and transmission). The expressions of cytokeratin-18 and α-SMA were measured by immunohistochemistry. RT-PCR and Western-blot were used to detect the expression of collagen type I. RESULTS: Cultured with TGF-β1 at concentration of 10 μg/L for 3 days, part of the NRK52E cells developed elongated shape, loss of microvilli and apical-basal polarity, and appeared bundles of actin microfilaments. The addition of 10 mg/L TGF-β1 neutralizing-antibody and 30 mg/L CTGF antisense oligonucleotides (ASON) almost completely blocked the morphological changes induced by TGF-β1, only a little hypertrophy was observed. Cultured with 10 μg/L TGF-β1 for 3 days, the expression of cytokeratin-18 significantly decreased, and α-SMA and collagen type I significantly increased. Treated with neutralizing-antibody, the expressions of cytokeratin-18, α-SMA and collagen type I were almost restored. Changes induced by TGF-β1 were not reversed by CTGF sense oligonucleotides (SON). CONCLUSION: It is demonstrated that CTGF as a TGF-β downstream cytokine mediates tubular-epithelial myofibroblast transdifferentiation.