Abstract
Abstract: :
Purpose: To understanding cell proliferations of corneal endothelium cells (CE) in central and peripheral corneas in response to contact inhibition that released by EDTA treatment and scrape wounding. Methods: Rabbit corneas were used and separated into two groups: 1. treatment with EDTA and 2. scraping with silicone needle. The effect of EDTA dose (2.0 & 0.2 mg/ml) and incubation time (30 minutes, 1 hour) on endothelial cell-cell junctions was evaluated by ZO-1 staining. Corneal pieces were pre-incubated for 0 and 24 hours in culture medium (M199, 10%fetal bovine serum) before EDTA treatment or scraping then were incubated with same medium for 24,48, 72 and 96 hours to permit cell cycle entry. Tissue was fixed at these time points and stained for Ki67, a cell marker for late G1-phase through the M-phase, and ZO-1. The cell proliferation, Ki 67 positive rate of CE, was evaluated in central 3 mm, mid-peripheral and peripheral corneas. EDTA effects on cell junctions were checked by the percentages of "ring-shaped" junction formation. Results: Rabbit CE could be reliably scored for their location within the cell cycle using Ki67 staining patterns. In scraping group, cells repopulating the wound area stained positively for ki67 with and without preincubation, whereas no ki67 staining was observed in EDTA treatment without pre-incubation. Preincubation in culture medium for 24 hours was needed for endothelial cells to efficiently initiate proliferation in response to EDTA. After preincubation, the initiation of proliferation in response to EDTA treatment was faster then wounding treatment, but wounding treatment had a longer response time until after treatment for 72 hours. In both groups, peripheral CE proliferate more actively then central CE. Conclusions: EDTA and scrape both released CE form contact inhibition and promoted proliferation. CE respond to these two treatments differently proliferated and peripheral CE proliferate much more significantly than Central CE in both conditions.
Keywords: cornea: endothelium • proliferation • wound healing