Measurement of corneal DNA content.

The amount of DNA in the corneal epithelium, stroma, and endothelium of both rabbit and bovine tissue was measured by a diphenylamine assay procedure. The results indicate that hot perchloric acid extraction is required to effectively solubilize the corneal DNA for assay. Rabbit corneal epithelium, stroma, and endothelium were found to contain 53.8, 1.7, and 4.3 microgram of DNA per milligram of tissue dry weight, respectively. Bovine corneal epithelium contained 15.8 microgram/mg DNA, stroma 0.6 microgram/mg DNA, and endothelium 3.1 microgram/mg. These data provide a basis for an expression of the cellularity of corneal layers.