Prevention of selenite-induced opacification and biochemical changes in the rat pup lens through amiloride pretreatment

Purpose. To determine the effects of amiloride on selenite-induced cataract s, to identify this agent's role as an antioxidant, and to study related ef fects on ion levels in the rat lens. Methods. Wistar albino rat pups were assigned to one of three groups, one c ontrol and two experimental. The first experimental group (Group 1; n = 22) received a subcutaneous injection of sodium selenite (30 nmol/g body weigh t) on postpartum day 10. The second experimental group (Group 2; n = 21) re ceived a subcutaneous injection of amiloride (1 nmol/g body weight) 15 minu tes before the sodium selenite injection. The control group (n = 22) receiv ed no injection. The pups in each group were observed during three weeks af ter the injection date. At the end of this period, the stage of cataract de velopment was identified by comparison with slit lamp photographs and then the pups were sacrificed and their lenses were removed intracapsularly usin g a posterior approach. Cation analysis was carried out and glutathione and malondialdehyde levels were measured for each group. Results. Cataract stage in Group 1 was significantly higher than Group 2. M ean cataract stages in Groups 1 and 2 were 3.8 +/- 0.12 and 1.6 +/- 0.25 re spectively. None of the control animals developed cataracts. Amiloride-pret reated group contained significantly higher glutathione levels than Group 1 . The level of malondialdehyde in Group 1 lenses was approximately twice th at in the lenses of the Group 2 amiloride+selenite-treated animals. The Ca2 + level was significantly higher in Group 1 lenses compared to the amilorid e-pretreated rats, but there was no significant difference between Groups 1 and 2 with regard to Na+ and K+ levels. Conclusion. Amiloride was very effective in preventing cataract formation i n the selenite-induced cataract model. This protective effect of amiloride was accompanied by higher glutathione levels and lower malondialdehyde leve ls in the rat pups' lenses compared to levels in animals that received sele nite alone. These results suggest an anti-oxidant role for this agent, in a ddition to its effects on lens ion homeostasis.