The Barrier Integrity And “Pump” Function Were Disrupted By Acute Ocular Hypertension In Rat Corneal Endothelial Cells

Purpose: The rapid increases in intraocular pressure(IOP) induce corneal edema in acute primary angle closure(APAC) patients. We want to investigate the disruptive effects of acute IOP rise on corneal endothelial cells(CECs) in rats.Methods: The SD rats' anterior chamber of the right eyes was irrigated with Balanced Salt Solution(BSS) for two hours and the left eyes as controls. IOPs were measured with handheld non-contact tonometer. At instantly, day 2 and day 7 after irrigation, corneal edema was observed by silt-lamp microscope. CECs quantity and proliferation were assessed separately by Alizarin Red Staining and Ki67 immunofluorescent(IF) staining. Their permeability was determined based on measurements of FITC-dextran tissue accumulation. Apical junctional complex(AJC) integrity and pump structure were evaluated of zonula occludens-1(ZO-1), filamentous actin(F-actin), as well as Na,KATPase by IF staining and western blot analysis.Results: The average IOP was 82.6 ± 2.3mm Hg(normal range: 10.2 ± 0.4 mm Hg) during anterior irrigation. Instantly after irrigation, corneal edema became notable and the permeability to FITC-dextran significantly increased. The peripheral endothelial cells density(ECD) was significantly reduced and the morphology of CECs became irregular and multiform. The structures of ZO-1 and F-actin were seriously disrupted. The expression pattern of Na,K-ATPase became scattered. Two days after irrigation, the proliferation of CECs was obvious and ECD recovered to normal level, and the distribution of F-actin was scattered to the whole cytoplasm. Seven days later, CECs structure and function nearly normalized except the distribution of F-actin.Conclusions: CECs structure and function were disrupted by AOH, which resulted in instantly corneal edema and the decreased endothelial cells density.