In order to investigate whether porcine eyes could be useful for trabecular meshwork (TM) organ culture, changes in ultrastructure and synthesis of glycosaminoglycans (GAGs) of organ-cultured porcine TM were studied. The presence of thrombospondin was also detected in porcine TM, using an immunohistochemical method. Explants were cultured for periods of 7 to 21 days and subsequently some of them were labeled with 3H-glucosamine and 35S-sulfate for 48 hours. There was very little change in the ultrastructure of the explants during our culture periods. The total incorporation of 3H-glucosamine and 35S-sulfate into trabecular GAGs for up to 21 days showed similar patterns. Immunoreactivity for thrombospondin was found in the trabecular sheets. This organ culture system suggests a model for studying the various drug and hormone induced alterations in this tissue.