Hales A M, Schulz M W, Chamberlain C G, McAvoy J W
Department of Anatomy and Histology, University of Sydney, NSW, Australia.
Curr Eye Res. 1994 Dec;13(12):885-90. doi: 10.3109/02713689409015091.
Spindle-shaped myofibroblast-like cells, which contain alpha-smooth muscle actin, have been described in anterior subcapsular cataract and after-cataract. In a previous study in this laboratory, it was shown that transforming growth factor-beta (TGF beta) induces the formation of spindle-shaped cells in lens epithelial explants. The aim of this investigation was to determine whether these TGF beta-induced spindle-shaped cells contain alpha-smooth muscle actin. Lens epithelial explants were prepared from 21-day-old rats and cultured with either TGF beta 1 or basic FGF alone, a combination of both growth factors, or without added growth factors. After three days, cellular changes were monitored by phase contrast microscopy, localisation of filamentous actin with rhodamine-phalloidin, and immunolocalisation and immunoblotting of alpha-smooth muscle actin. TGF beta induced rapid cell elongation and formation of characteristic spindle-shaped cells in lens epithelial explants in the presence or absence of FGF. These cells contained alpha-smooth muscle actin, a marker for myofibroblastic cells and a protein not normally found in the lens. The present study thus provides molecular evidence that TGF beta induces cataractous changes in lens epithelial cells. As TGF beta is potentially available to lens cells in situ throughout life, these findings are consistent with a key role for TGF beta in the aetiology of major forms of subcapsular cataract.
在晶状体前囊下白内障和后发性白内障中已发现含有α-平滑肌肌动蛋白的梭形肌成纤维细胞样细胞。在本实验室先前的一项研究中，已表明转化生长因子-β（TGF-β）可诱导晶状体上皮外植体中梭形细胞的形成。本研究的目的是确定这些由TGF-β诱导的梭形细胞是否含有α-平滑肌肌动蛋白。从21日龄大鼠制备晶状体上皮外植体，并分别用TGF-β1或碱性成纤维细胞生长因子（basic FGF）单独培养、两种生长因子联合培养或不添加生长因子进行培养。三天后，通过相差显微镜监测细胞变化，用罗丹明-鬼笔环肽检测丝状肌动蛋白的定位，并用免疫定位和免疫印迹法检测α-平滑肌肌动蛋白。无论有无FGF，TGF-β均可诱导晶状体上皮外植体中的细胞迅速伸长并形成特征性的梭形细胞。这些细胞含有α-平滑肌肌动蛋白，这是肌成纤维细胞的标志物，也是晶状体中通常不存在的一种蛋白质。因此，本研究提供了分子证据，证明TGF-β可诱导晶状体上皮细胞发生白内障样变化。由于TGF-β在一生中晶状体细胞原位都可能存在，这些发现与TGF-β在主要形式的囊下白内障病因学中的关键作用相一致。
