Proliferative activity and cell differentiation during the period of intensive growth of the iris, ciliary body and pupillary sphincter in rats
Stroeva, O.G.; Marashak, T.L.; Lobacheva, V.A.
Tsitologiia 19(5): 495-500
1977
ISSN/ISBN: 0041-3771 PMID: 888206 Document Number: 119502
The duration of the cell cycle in the sphincter pupillae and in the inner and outer neuroepithelia of the iris and ciliary body was studied. The four-day old rats were injected H3-thymidine and three-day old animals were administered H3-dopa to be processed for autoradiography. Cells of sphincter and of both neuroepithelia of the iris have the doubling time of 9.2--9.8 days, whereas the doubling time of cells of neuroepithelia of the ciliary body reaches 5.3--5.9 days. All pigmented epithelia of the iris-ciliary body complex synthesize melanin with the same intensity despite their specific differentiation. The most differentiated smooth muscle cells localized at the outer surface of the sphincter have almost half a melanin synthetic activity as compared with that of more deeply laying cells. Mitotic and H3-thymidine labelled cells were observed in all the areas of the sphincter. The data obtained were interpreted in terms of possible compatibility of both processes in smooth muscle cells of the iris; the synthesis of contractile proteins and the mitotic activity. The cell proliferation and differentiation of the structures in question were regarded as processes being regulated independentely at the stage studied.