Growth factors influence contractility and alpha-smooth muscle actin expression in bovine lens epithelial cells

Invest Ophthalmol Vis Sci. 1995 Jul;36(8):1701-8.


Purpose: To determine whether basic fibroblast growth factor (bFGF) and transforming growth factor-beta 2 (TGF-beta 2) influence the contractile activity and the expression of alpha-smooth muscle actin (alpha-SMA) in bovine lens epithelial cells (LECs). To examine whether modulation of contractile activity by these growth factors depends on changes of alpha-SMA expression.

Methods: Bovine LECs were cultured in collagen gel in MED 5 medium (F-12 nutrient mixture supplemented with 5% fetal bovine serum) with or without bFGF (1 to 100 ng/ml) or TGF-beta 2 (0.01 to 10 ng/ml). To evaluate collagen gel contraction, the longest and shortest diameters of the gels were measured daily for 7 days, and the area was determined. Detection of alpha-SMA in the gels was performed immunohistochemically using a mouse monoclonal antibody against alpha-SMA. The percentage of alpha-SMA-positive cells to the total number of cells was determined.

Results: Control gels cultured with MED 5 medium alone contracted to 15.8% +/- 3.4% of their original area after 7 days. TGF-beta 2 significantly increased this contraction in a dose-dependent manner, whereas bFGF significantly decreased it. Approximately 30% of cells in the control gels were alpha-SMA positive. TGF-beta 2 significantly increased the alpha-SMA positivity dose dependently, whereas bFGF significantly decreased it. The percent positivity for alpha-SMA and the gel area showed a significant negative correlation.

Conclusions: TGF-beta 2 increased collagen gel contraction and alpha-SMA expression in bovine LECs, whereas bFGF decreased these parameters. Because collagen gel contraction was correlated with alpha-SMA expression, the modulation of LEC contractile activity by growth factors may be related to an effect on alpha-SMA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / biosynthesis*
  • Animals
  • Cattle
  • Cell Movement / drug effects
  • Cell Size / drug effects
  • Cells, Cultured
  • Collagen / metabolism
  • Dose-Response Relationship, Drug
  • Epithelium / drug effects
  • Epithelium / metabolism
  • Fibroblast Growth Factor 2 / pharmacology*
  • Gels
  • Immunoenzyme Techniques
  • Lens, Crystalline / cytology
  • Lens, Crystalline / drug effects
  • Lens, Crystalline / metabolism*
  • Muscle, Smooth / metabolism*
  • Transforming Growth Factor beta / pharmacology*


  • Actins
  • Gels
  • Transforming Growth Factor beta
  • Fibroblast Growth Factor 2
  • Collagen