Spindle-shaped myofibroblast-like cells, which contain αsmooth 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-β (TGFβ induces the formation of spindle-shaped cells in lens epithelial explants. The aim of this investigation was to determine whether these TGFβinduced spindle-shaped cells contain αsmooth muscle actin. Lens epithelial explants were prepared from 21-day-old rats and cultured with either TGFβ1 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 αsmooth muscle actin. TGFβ 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 αsmooth muscle actin, a marker for myofibroblastic cells and a protein not normally found in the lens. The present study thus provides molecular evidence that TGFβ induces cataractous changes in lens epithelial cells. As TGFβ is potentially available to lens cells in situ throughout life, these findings are consistent with a key role for TGFβ in the aetiology of major forms of subcapsular cataract.
- Transforming growth factor-β
- αsmooth muscle actin