Cell death in exorbital lachrymal gland of anophthalmic mutant rat during postnatal development.

Regression in the exorbital lachrymal gland was observed in congenital blind mutant rats lacking eyeballs and optic nerves. The morphological changes during postnatal development in acinar cells of the lachrymal gland of mutant rats were compared with those of normal rats at day 13 (before the opening of the eyes), day 30 (15 days after opening of the eyes) and the adult (90 days). Atrophy of the lachrymal gland is most likely to be associated with absence of functional signals. During regression, there is a massive elimination of cells from the acini; no fibrosis or immune reaction (lymphocytic infiltration) was observed in the gland. This atrophy in the lachrymal gland of blind rats was not associated with the biochemical markers of apoptosis. Present observations indicate that cell elimination from the lachrymal gland in blind rats is a special type of apoptosis, where cell homeostasis is not required.