Comparative ultrastructural study of rabbit Müller cells in vitro and in situ.

The ultrastructural appearance of cultured rabbit glial cells (putative Müller cells) has been compared with that of rabbit Müller cells in situ. Electron microscopy disclosed that the cultured cells had a basement membrane comparable to the inner limiting membrane of the retina and that villous processes adjacent to zonulae adherentes were reminiscent of fibre baskets and the outer limiting membrane. Cultured cells showed apico-basal polarisation in specimens from early passages. It was noted however that cultured cells showed a number of features which were different from normal Müller cells in situ. These included prominent rough endoplasmic reticulum, sparse smooth endoplasmic reticulum and relatively electron lucent cytoplasmic matrices. These findings resembled the appearances found in proliferating Müller cells in the human eye. The ultrastructural differences noted in the cultured Müller cells suggest that the cultured cells are in an active form.