DECREASED RHODOPSIN REGENERATION IN DIABETIC MOUSE EYES

Purpose. To evaluate the effect of diabetes on rhodopsin regeneration in the excised mouse eye. Methods. A superfused excised mouse eye prep aration that exhibits rhodopsin regeneration after moderate bleaches a nd that is responsive to the composition of the perfusate was used. Di abetes was induced in albino mice (BALB/c) with the diabetogenic agent streptozotocin. Absorption spectrophotometry of the excised eye was u sed to monitor rhodopsin concentrations. Results. Significant reductio ns in rhodopsin regeneration were observed in diabetic mice. Severely diabetic mice exhibited only 64% and 55% regeneration (at perfusate gl ucose levels of 5.1 mM and 10 mM, respectively), and moderately diabet ic mice exhibited 74% and 73% regeneration, compared to the greater th an 100% regeneration observed in nondiabetic mice. Glucose perfusate c oncentration has a major effect on rhodopsin regeneration. Lower conce ntrations of perfusate glucose (3 mM) reduced the amount of rhodopsin regeneration in both nondiabetic mice and diabetic mice. The diabetic mice seemed to tolerate higher concentrations of perfusate glucose (20 mM) better than the nondiabetic mice. Neither correction for osmolari ty nor substitution with a nonglycolytic substrate increased the amoun t of rhodopsin regeneration in the diabetic mice. Conclusions. Diabete s reduced the amount of rhodopsin regeneration that followed moderate bleaches in excised mouse eyes. The data suggest that some process or processes associated with rhodopsin regeneration have been affected in the diabetic.