Cytological study of philly mouse cataract

Lenses of Philly mouse, a new congenital cataract animal model derived from Swiss Webster mice, were studied by light and electron microscopy. The lenses developed normally until the first postnatal week. In the beginning of the second postnatal week an early cataractous change was noted due to the appearance of particles in the bow cortex. By the 10th day, distribution of the particles extended mainly to the anterior subcapsular area of the lens cells. Two weeks after birth, enlargement of persisting bow nuclei became prominent. On about the fourth postnatal week, when posterior lens fibers were swollen, degenerating cells and large intercellular spaces were present in the superficial bow cortex. Between five and seven weeks, epithelial cells at the equator became tall, and the number of their mitotic figures was markedly reduced. The lens cells in the posterior cortex became degenerative causing the widening of the posterior suture. At this stage the lenticular nucleus became markedly opaque. These findings suggest that the lens cells of the Philly mouse maintained normal function only until the 7th postnatal day and that the marked loss of differentiating ability causes subsequent cytological changes in various areas of the lens.