EFFECTS OF HYPERCAPNIA ON CORNEAL EPITHELIUM

Title EFFECTS OF HYPERCAPNIA ON CORNEAL EPITHELIUM
Author, Co-Author Mosa'a Al-abdulmunem, Jan Bergmanson, Nathan Efron
Topic
Year
1994
Day
Tuesday
Program Number
Poster 9
Room
Marriott Hall 3
Affiliation
Abstract This study is designed to evaluate the effect of carbon dioxide accumulation in the corneal epithelium at a cellular and subcellular level. In presenting carbon dioxide to the cornea gases were prefered over occlusion through contact lenses since contact lenses may cause superficial trauma which may be confused with changes provoked by hypercapnia alone. Gases were first bubbled through distilled water and thereafter passed through tight fitting goggles with inlet and outlet tubing. The experimental corneas of three rabbits were exposed to 7% CO2, 5% CO2 and 2% CO2. Balance air at 35 deg. C for four hours. The contralateral eye received a normal air mixture in exactly the same manner the carbon dioxide was presented. Two further rabbits were used as controls and did not wear goggles. Immediately following the exposure, the eyes were removed, placed in Karnovsky`s fixative and prepared for transmission electron microscopy. Evaluation of the tissue showed electron dense membrane bounded structures filled with granular material, 'granular acidic pools (GAP),' which were found most predominantly in squamous and wing cell layers appearing either inside or around the cell membrane. A large number of disintegrated mitochondria (DM) were observed throughout the epithelial layers. An increased in cell sloughing and a reduction in microvilli among surface cells was also recorded. We suggest that hypercapnia-induced acidic shift in the epithelium results in local biochemical reactions at cellular membranes thereby producing osmio-philic granular compounds, GAP, which diffuse into cells through pinocytosis. As cellular pH drops, cellular ATP concentrations falls which results in ion accumulation by mitochondria leading to DM.
Affiliation of Co-Authors
Outline