Cell contacts and smooth muscle bundle formation in tissue transplants into the anterior eye chamber

Summary Segments of the taenia coli from guinea-pig were transplanted into the anterior chamber of the eye. Depending on such factors as the total volume of the transplant and the presence or absence of ganglion cells degeneration was either very extensive (90% or more of the total number of muscle cells) or localized (alternating regions of degenerating and normal structure). During days 1–2 muscle cells lost their plasma membranes so that their cytoplasmic contents were dispersed into the intercellular spaces. Many cells produced numerous small processes which were pinched off and dispersed in a similar manner. Following a period of intense mitotic activity (3–8 days) numerous cells with the characteristics of embryonic smooth muscle cells were evident. Within 10–14 days these differentiating cells produced bulbous protrusions and assumed more irregular outlines than at 3–8 days. The protrusions formed close contacts (50–100Å intercellular space) and tight junctions between adjacent muscle cells. Aggregation of muscle cells into bundles was under way between 14–28 days. At approximately 4–6 weeks these developing muscle groups were invaded by nerve fiber bundles. The pattern of the innervation and the form and size of the muscle bundles simulated the normal. These findings are discussed in relation to the possible functions of the intercellular contacts and cellular protrusions which characterise various periods of regeneration.This work was supported by the Australian Research Grants Committee. The transplants were carried out by Dr. T. Malmfors assistant, Miss Ulla Enberg.