Abstract
Purpose: :
To prevent the proliferation and differentiation of lens epithelial cells in the posterior capsular opacification (PCO) in pig eye capsular bag model by inhibiting aldose reductase (AR).
Methods: :
Pig eye capsular bags were prepared by capsulorhexis and cultured in complete growth medium with or without AR inhibitor for 7 days. Medium was replaced with fresh medium without or with AR inhibitor every day. At the end of incubation, capsular bags were cut in 4 pieces and flat mounted on glass slide with cellular part facing up, washed with cold PBS and fixed with 4% paraformaldehyde. The specimens were immuno-stained using proliferating cell nuclear antigen (PCNA), and the differentiation markers e.g. α- smooth muscle actin (SMA), β-crystalline and ICAM-1 antibodies. Also, the cells were trypsinized and counted manually to assess the cell growth. Further to investigate the mechanism by which AR inhibition prevents PCO, we examined the effect of AR inhibition on FGF-induced mitogenic signaling events in cultured human lens epithelial cells (HLEC). Cell growth was assessed by MTT assay and counting the number of cells. The differentiation markers and protein kinases were assessed by Western Blot and immunocytochemical analysis. Gel shift as well as gene reporter assays were performed to determine activation of NF-ΚB.
Results: :
The pig eye capsular bags showed vigorous growth of lens epithelial cells both in the anterior and posterior capsular walls. Treatment with AR inhibitor (ARI) significantly prevented the lens epithelial cell growth in capsular bags and expression of differentiation markers such as α-SMA and β-crystalline. The HLEC showed dose dependent response to FGF, proliferating at lower concentration while at higher concentration of FGF the cells begin differentiating as evident by the expression of differentiation markers such as α-SMA, β-crystalline, ICAM-1, and filensine. Treatment with FGF caused phosphorylation and activation of MAPK e.g. ERK1/2, and JNK, and also activated NF-ΚB in HLEC, which were inhibited by ARI.
Conclusions: :
Our results suggest that inhibition of AR prevents the proliferation and differentiation of lens epithelial cells after capsulorhexis in pig eye capsular bags as well as in cultured HLEC, indicating a potential therapeutic role of AR inhibitors in prevention of PCO.
Keywords: posterior capsular opacification (PCO) • enzymes/enzyme inhibitors • growth factors/growth factor receptors