Toxic effects of ouabain on the rabbit corneal endothelium

Rabbit corneas kept in a standard tissue culture medium, were continually exposed to ouabain 10(-3) M, and cultivated for 2, 3 and 4 days. The endothelium was still intact with a complete cell cover after 2 days of ouabain exposure. Total destruction of the endothelium was found in the corneas cultivated for 3 and 4 days. The corneal epithelium, however, appeared to be unaffected. Other rabbit corneas were exposed for three days to ouabain concentrations of 10(-4) M, 10(-5) M, 10(-6) M, 10(-7) M, 10(-8) M, and 0 M. The corneas exposed to 10(-4) M demonstrated total endothelial cell damage. The specimens exposed to concentrations from 10(-5) to 10(-8) M, presented dose dependent endothelial impairment as compared with the control corneas (0 M). Tracer experiments showed that the endothelial barrier was intact as long as there was a continuous cell cover, as estimated by light, transmission and scanning electron microscopy.