[Effect of Smad 4 mRNA on the proliferation of rabbit epithelial cells]

To assess the effects of Smad 4 mRNA on the proliferation and transformation of rabbit lens epithelial cells (LECs).

The expressions of Smad 4 mRNA and proliferating cell nuclear antigen (PCNA) in rabbit LECs in different periods after lens cortex absorption were detected by in situ hybridization (ISH) and immuno-histochemical methods respectively.

(1) The expression of Smad 4 mRNA in the cytoplasm of normal rabbit lens epithelial cells was weakly positive. (2) The expression in the equatorial region and anterior subcapsular region on the postoperative first day was negative, and the light absorbance (A) was 0.39 and 0.36 respectively, P < 0.01 in comparison with the preoperative ones. (3) The expression of Smad 4 appeared again on the postoperative third day, and then increased gradually along with the prolongation of time. The expression of Smad 4 mRNA of cells in anterior subcapsular region reached its peak in the postoperative one month. The percentage of positive area was 1.31 and the average A value was 0.54. In the equatorial region, the expression was strongest in the postoperative one week, the percentage of positive area was 0.77 and the A value was 0.53, P < 0.01 in comparison with that before the operation. (4) In 1 - 2 months postoperatively, transformed fibroblasts appeared in the equatorial region. The expression of Smad 4 mRNA was positive in the cytoplasm of the transformed fibroblasts. The expression of PCNA was strongest on the postoperative first day, and afterwards it was gradually decreased. Until the postoperative one month, it restored to its preoperative level.

The expression of Smad 4 mRNA presents in normal lens epithelial cells. Smad 4 mRNA participates in the proliferation and metabolism of lens epithelial cells. Smad 4 mRNA possibly participates in the procedure of transformation from lens epithelial cells to fibroblasts.