Fine structural changes in the fibroblasts of canine heart valves prepared for grafting.

, , 748-755. Fibroblasts in canine heart valves were examined by light and electron microscopy after one, two, and three weeks' exposure to Hanks's balanced salt solution and to three series of antibiotic solutions used in preparing heart valve allografts. Condensation of chromatin, degeneration of mitochondria, dilatation and loss of endoplasmic reticulum, and rupture of cellular membranes were observed in a proportion of fibroblasts exposed to Hanks's solution for longer than one week and in all specimens treated with antibiotics. These changes became more frequent and severe as the exposure to these solutions increased and they were not reversed nor inhibited by the inclusion of a tissue culture medium in the mixture. These findings are discussed in relation to the role of donor fibroblasts in heart valve allografts.