Immunocytochemical localization of cyclooxygenase in the rat lens

The localization of rat lens fatty acid cyclooxygenase (prostaglandin synthase) was studied using indirect immunofluorescent and indirect streptavidin-biotin immunoperoxidase staining techniques. Both methods employed monoclonal and polyclonal antibodies directed against fatty acid cyclooxygenase, the key enzyme in the conversion of arachidonic acid to prostaglandins. The immunocytochemical studies demonstrate that (1) fatty acid cyclooxygenase is present in the rat lens epithelial cell layer; (2) the enzyme appears predominantly in the cytoplasm; (3) there is an apparent higher concentration of the enzyme in the region designated as germinative and transitional zones, and meridional rows; and (4) the enzyme appears to be absent in the lens capsule and in the nucleus of the lens. The presence of the cyclooxygenase enzyme in the lens epithelium, especially the relative intense staining in the epithelial mitogenic region, suggests that oxygenation of polyunsaturated fatty acids by the fatty acid cyclooxygenase may have an important role in cellular differentiation.