The lens epithelium and radiation cataract. IV. Ultrastructural studies of interphase death in the meridional rows.

The effect of radiation upon the differentiating meridional row cells of the rat lens epithelium was studied by electron microscopy. X-irradiation of rat lenses was shown to disrupt the nuclear and, in some instances, the cytoplasmic organization of these cells. Indications of damage, 4.5 h post-irradiation, are a disruption in the shape of the nucleus and its membranes. This is typified by a bulging or blebbing of the nucleus. At 12 h the affected nuclei deteriorate with obvious membrane breakdown. The nucleoplasm at this time may appear highly condensed and shrunken. Disruption of the plasma membrane is also evident. Based upon previous findings it is likely that the nuclear changes are independent of the processes involved in normal fiber denucleation.