Abstract
Abstract: :
Purpose: In recent years, it has been indicated that medical agents that increase the mucin in tears can be used to treat dry-eye patients. We have demonstrated that OPC-12759 ophthalmic suspension increases the level of mucin in rabbit ocular surfaces. However, it is not clear what mucin producing cells (corneal and conjunctival epithelial cells, goblet cells) OPC-12759 affects to increase mucin. In this study, we used cultured human corneal epithelial cells (HCEC, KURABO), measured the mucin amount in the supernatant as well as within the cells and examined the mucin increasing effect of OPC-12759. Methods: The amount of mucin was measured by the combined methods of gel filtration (Sepharose CL-4B) and enzyme-linked lectin assay (ELLA). In the ELLA method, wheat germ agglutinin (WGA) was used as the lectin and bovine submaxllary mucin was used as the standard. HCECs were incubated in a serum-free EpiLifeTM medium until reaching a confluent condition and, after having added OPC-12759 or not, the amount of mucin in the supernatant as well as within the cells was measured. Results: In the OPC-12759 10-5M group, the mucin amount in the supernatant significantly increased compared with the control group 12 and 24 hours later (p<0.01). And, 24 hours was the point showing the highest increase amount. The result of examining the dose dependent effect of the mucin increasing effect of OPC-12759 24 hours later showed a gradual increase in mucin amount in the supernatant of the 10-7M group and, in the 10-5M as well as the 10-4M groups, there was a significant increase of 1.4 times the control group (p<0.01). Also, the result of measuring the mucin amount in cells showed an approximate 2.0 to 2.5-fold increase in the OPC-12759 10-5M and 10-4M groups compared to the control group (p<0.01). Conclusions: From the increase in the amount of mucin in the HCEC supernatant, it was indicated that OPC-12759 renders possible the promotion of soluble mucin secretion from human corneal epithelial cells. Because of the increase in mucin amount in the HCEC, we believe that within the cells, the increase in the expression of soluble mucin synthesis or of membrane binding mucin is possible. Hence, it is indicated that OPC-12759 may be used as a dry-eye treatment medication that promotes the secretion and synthesis of mucin in HCECs.
Keywords: cornea: surface mucins • drug toxicity/drug effects • cornea: epithelium