PGE(2) SYNTHESIS AND RESPONSE PATHWAYS IN CULTURED CORNEAL ENDOTHELIAL-CELLS - THE EFFECTS OF IN-VITRO AGING

Purpose. The purpose of these studies is to develop an in vitro model of corneal endothelial aging and to investigate age-related changes in morphology, mitosis, prostaglandin synthesis and prostaglandin respon se pathways. Methods. First-passage rabbit corneal endothelial cells w ere grown in vitro for up to 30 days after subculture. PGE(2) synthesi s was measured by radioimmunoassay. EP2 receptors were evaluated by de termination of PGE(2) stimulated cyclic AMP synthesis. Cell-cycle para meters were evaluated by flow cytometry and by bromodeoxyuridine (BrdU ) incorporation in subconfluent, confluent and Injured cultures. Resul ts. Rabbit corneal endothelial cells become less dense and more irregu lar in shape as they age in culture, thus resembling their in vivo cou nterparts. PGE(2) synthesis and response decrease with culture age. In jury results in enhanced PGE(2) synthesis in both younger and older cu ltures. In younger cultures, injury also results in mitosis of cells a t the wound margin, and this response is greatly diminished in older c ultures. Conclusions. The morphologic and mitotic changes seen in rabb it corneal endothelial cultures in vitro resemble those seen as a cons equence of aging in humans and rabbits. Prostaglandin synthesis and re sponse pathways are modified as a result of aging and may play a role in the autocrine regulation of wound repair, especially in younger cel ls.