Interactions of Corneal Endothelial Cells with Stromal Cells during Corneal Endothelial Injury

Abstract

Purpose: To investigate the interaction of corneal endothelial cells (CECs) with corneal stromal cells (CSCs) on the healing of chemically induced corneal endothelial injury.

Methods: New Zealand white rabbits were injected with 0.1 mL of 0.05N NaOH into the anterior chamber for 10 min. Corneal edema and thickness were evaluated at day 1, 7, 14 and 28 after endothelial injury. Vital staining with alizarin red and trypan blue was performed. Immunofluorescein staining of collagen VIII alpha2 (COL8A2), glial fibrillary acidic protein (GFAP), and alpha-smooth muscle actin (α-SMA) and deoxynucleotidyltransferase (TdT)-mediated dUTP nick end labeling were performed. Human corneal endothelial cells (HCECs) and CSCs were co-cultured in a Transwell system. Concentration of transforming growth factor-beta1 (TGF-β1)and interleukin-6 (IL-6)in the media was measured by an enzyme-linked immunosorbent assay. Intracellular expression of COL8A2 were evaluated by western blotting.

Results: Corneal edema and corneal opacity scores were higher in all rabbits exposed to NaOH than in controls. Corneal endothelial apoptosis with minimal damage to CSCs was observed in rabbits exposed to NaOH at day 1, and CECs migrated from the periphery. Two weeks after injury, CSCs were aligned in parallel to the Descemet's membrane, which exhibited the presence of CECs. TGF-β1and IL-6 secretion was lower in the co-culture system than inindividual cultures of HCECs or CSCs. COL8A2 expression was higher in HCECs co-cultured with CSCs compared to the HCECs only without CSCs.

Conclusions: Intracameral NaOH injection is a model of corneal endothelial injury with minimal impact on the stroma. Communication between CECs and CSCs during wound healing may lead to the modulation of cytokine production, which is necessary for an enhanced healing process of corneal endothelial injury.