Sialomucin complex (rMuc4) expression during development of the rat cornea.

Purpose. To determine changes in sialomucin complex (SMC, rat Muc4) expression in rat ocular surface tissue during development from birth to adult. Methods. Immunoblot and immunocytochemical analyses were performed on isolated corneal tissue and rat eyes, respectively, from animals at days 1, 9 and 15 after birth. Adult animals were used for comparison. Results. SMC was detected by immunoblotting at all ages (day 1-adult) and increased into adulthood. Immunocytochemical localization also showed steadily increasing amounts of SMC to adulthood. The SMC was located at the apical surface of the corneal epithelium and in the superficial layers of the stratified corneal epithelium. Conclusions. SMC at the corneal surfaces steadily increases during development to adulthood, but does not exhibit a marked transition in expression at the time of eye-opening.