Modelling cortical cataractogenesis. XII: Supplemental vitamin A treatment reduces gamma-crystallin leakage from lenses in diabetic rats.
Normal and streptozotocin diabetic female Wistar rats were given normal diets with the following additions: 0, or 12,500 iu/kg food vitamin A (retinyl palmitate). At the end of 6 weeks, the rats were examined for weight gain or loss, general body condition, and cataracts. At sacrifice, blood was collected for measurement of serum glucose. gamma-Crystallin levels were determined in aqueous and vitreous humours using a radioimmunoassay. One lens (the right) was homogenized in 8 M guanidinium chloride for ATP analysis. In normal rats, gamma-crystallin was detected in both aqueous and vitreous humours, with a greater concentration found in the vitreous. Diabetes caused a 4-5 fold increase in gamma-crystallin in both aqueous and vitreous humours. Diabetes also led to a significant loss of body weight, and decrease in lens ATP levels. Addition of vitamin A to the diet resulted in reduction in gamma-crystallin leakage into the aqueous and vitreous humours. Vitamin A at 12,500 iu/kg food resulted in an increase in lens ATP for the diabetic rats. Neither streptozotocin diabetes nor vitamin A in the diet appeared to affect the weight of the lenses after 6 weeks. It is suggested that childhood vitamin A deficiency leading to latent fiber cell damage may be an important factor contributing to the high incidence of cataracts in the third world.
Linklater
H A
HA
Department of Biochemistry, University of Western Ontario, London, Canada.
Dzialoszynski
T
T
McLeod
H L
HL
Sanford
S E
SE
Trevithick
J R
JR
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism; D001835:Body Weight; D002386:Cataract / Q000378:metabolism*; D003459:Crystallins / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000378:metabolism*; D005260:Female; D007908:Lens, Crystalline / Q000378:metabolism*; D009929:Organ Size; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013311:Streptozocin; D014801:Vitamin A / Q000008:administration & dosage*; D014822:Vitreous Body / Q000378:metabolism
D003459:Crystallins; D014801:Vitamin A; D013311:Streptozocin; D000255:Adenosine Triphosphate