Long-term effects of a single dose of ultraviolet-B on albino rabbit cornea--II. Deturgescence and fluid pump assessed in vitro.

Both eyes of female albino rabbits (1.9 kg: 9-10 wk old) were exposed to a single dose of UV-B (300 +/- 9 nm; 0.125 J/cm2 total dose) between 13.30 and 15.00 h. At various time periods thereafter (every 12 h for 3 days, 6, 7, 14, 28, 42, 56, 112, 224 and 336 days post-irradiation), animals were sacrificed, samples of aqueous humor taken for analysis and stroma-endothelium preparations obtained from the corneas. Following such threshold irradiation, small increases in aqueous humor tonicity and protein levels were observed. The preparations were mounted in a specular microscope assembly (for measuring the rate and magnitude of corneal deturgescence) or between two half chambers (for measuring fluid pump) and equilibrated for 2 h with a CO2-equilibrated glucose-adenosine-glutathione-supplemented Ringer solution at 37 degrees C and a hydrostatic pressure of 20 cm H2O. After equilibration the stromal thickness showed large variation with large reductions in both the rate and amplitude of deturgescence function observed by 36 h. Large reductions in fluid pump activity were also observed by 36 h. The magnitude of the effects on fluid pump were somewhat greater than the effects on deturgescence. Both functions recovered to pre-irradiation levels by 112 days post-irradiation.