Changes in expression and distribution of lactate dehydrogenase isoenzymes in the developing chick retina

We have investigated the expression and distribution of lactate dehydrogenase (LDH) isoenzymes in the developing and adult chicken retina. Non-denaturing polyacrylamide gel electrophoresis was used to follow the appearance and expression of the five main LDH isoenzymes in tissue homogenates. Immunohistochemistry was used to define the distribution of the aerobic heart type LDH and the anaerobic muscle type LDH in paraffin sections of embryonic and adult chick retina. The electrophoretic results show that the expression of the anaerobic isoenzyme increases in the retina as development proceeds. Immunoreactivity against the anaerobic isoenzyme localizes to the inner plexiform layer and other regions of the inner chick retina. The aerobic isoenzyme immunoreactivity is localized to the inner segments of the photoreceptor cells as well as the ganglion cell layer. Both antibodies bind weakly in other layers of the retina with the notable exception that the anaerobic protein does not localize in the photoreceptor cell inner segments. These results provide further evidence for the anaerobic nature of the adult inner retina. As retinal development proceeds, the expression of the anaerobic isoenzyme in the retina increases.