Development and plasticity of the retina in the opossum Monodelphis domestica

We investigated the rate of cell proliferation and death in the retina of the Monodelphis opossum during its postnatal development and the influence of early monocular enucleation on these processes. Our results show that in the opossum, as in other marsupials, the peak of the retinal cells divisions occurs postnatally and that generation of retinal cells continues till the time of eye opening (P34), except of the marginal rim, where it continued till P60. Ganglion and amacrine cells are generated between postnatal days (P) P4 and P9, while bipolar cells and photoreceptors are generated simultaneously between P14 and P25. The peak of ganglion cell death as detected by the TUNEL method occurs around P14-19 in the center of retina. The second peak of apoptosis appears in the inner nuclear layer (INL) at P19-25. Gliogenesis takes place between P25 and P34. We also found that monocular enucleation performed during the early period of retinal development (P0-P7) did not influence proliferation, developmental apoptosis or other developmental processes in the retina of the remaining eye.