Developmental Histochemistry of the Rat Eye

¹ Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Md., and the Division of Ophthalmology, Department of Surgery, Sinai Hospital, Baltimore, Md.

A study of the development of the rat eye was undertaken with the histochemical demonstration of five oxidative enzymes to correlate patterns of oxidative enzyme activity with morphologic development. Succinic dehydrogenase, TPN and DPN diaphorase and two DPN-dependent enzymes, malic and lactic dehydrogenase, were demonstrated, and the histochemical patterns xoere examined in relation to the standard hematoxylin and eosin pattern obtained at seven periods during the development of the eye.

The immature rat eye, especially the developing retina, was found to have a significant level of oxidative enzyme activity. The pattern of enzyme localization in the outer layers of the retina appeared much before the morphologic differentiation of the retina. Mueller's fibers could be demonstrated histochemically only at a very late stage of development. In some of the enzyme preparations, such as succinic dehydrogenase and TPN diaphorase, the development of the immature patterns differed, in some respects, from the development of the other enzyme patterns. As the retina and the rest of the eye matured, however, the histochemical patterns gradually approached those of the adult.