Tomasz Dzialoszynski

Modelling cortical cataractogenesis VIII: Effects of butylated hydroxytoluene (BHT) in reducing protein leakage from lenses in diabetic rats

Normal and streptozotocin diabetic female Wistar rats were given butylated hydroxytoluene at 0-, 0.067- or 0.50% w/w in the diet. At the end of 10 weeks, the animals were examined for weight gain or loss, general body condition, and cataracts. After death, blood was collected for measurement of serum glucose. gamma-Crystallin was determined in aqueous and vitreous humours using a radioimmunoassay. One lens from each rat was homogenized in 8 M guanidinium chloride for adenosine triphosphate analysis. In normal rats, there is a small amount of gamma-crystallin found in the vitreous humour, and an even smaller amount in the aqueous humour. Diabetes caused a 2.5-fold increase of gamma-crystallin in the aqueous humour and a five-fold increase in the vitreous humour. Diabetes also led to a significant worsening in general body condition, loss of body weight, decrease in lens adenosine triphosphate levels, and formation of cataracts. Addition of butylated hydroxytoluene (BHT) to the diet resulted in improved general body condition, reduction in cataracts, decrease of gamma-crystallin leakage into the vitreous humour, and weight gain. There was no effect of dietary butylated hydroxytoluene on levels of lens adenosine triphosphate. Neither the diabetic state nor treatment with butylated hydroxytoluene affected the weight of the lenses.

Modelling cortical cataractogenesis. XI. Vitamin C reduces γ-crystallin leakage from lenses in diabetic rats

Normal and streptozotocin diabetic female Wistar rats were given vitamin C (VC) at 0.3% or 1.0% (w/w) in the diet: 1% dietary VC resulted, in 12-24 hr, in significant increases in serum ascorbate levels and lens ascorbate concentrations in normal rats. The increase was biphasic, with VC concentrations falling to a lower level which was still significantly elevated compared to controls in the period of 1.7-4 days for serum and 1.7-5 days for lenticular VC. At the end of 10 weeks the rats were examined for weight gain or loss, general body condition and cataracts. At the time of killing, blood was collected for measurement of serum glucose. Alpha-crystallin levels were determined in vitreous and aqueous humours using a radioimmunoassay. One lens from each rat was fixed for either scanning electron microscopy or light microscopy; the other lens was homogenized in 8 M guanidinium chloride for adenosine triphosphate analysis. In normal rats, a small amount of gamma-crystallin was found in the vitreous humour, and an even smaller amount in the aqueous humour. Diabetes caused a five-fold increase in the vitreous humour and a 2.5-fold increase in gamma-crystallin in the aqueous humour. Diabetes also led to a significant worsening in general body condition, loss of body weight, formation of cataracts, and decrease in lens adenosine triphosphate levels. Addition of VC to the diet of diabetic animals resulted in reduction in cataracts and a decrease of gamma-crystallin leakage into the aqueous and vitreous humours. VC had no effect on lens adenosine triphosphate levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Modeling Cortical Cataractogenesis: IX Activity of Vitamin E and Esters in Preventing Cataracts and γ‐Crystallin Leakage from Lenses in Diabetic Rats

Normal and streptozotocin diabetic female Wistar rats were given vitamin E in the diet as the tocopherol, acetate, or succinate form (2,850 IU/kg food). 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, and gamma-crystallin levels were measured in aqueous and vitreous humors using a radioimmunoassay. One lens was homogenized in 8 M guanidinium chloride for ATP analysis. In normal rats, gamma-crystallin was detected in both aqueous and vitreous humors, with the higher concentration in the vitreous humor. Diabetes caused a sixfold increase in gamma-crystallin in both the aqueous and vitreous humors. Diabetes also led to a significant worsening in general body condition, loss of body weight, formation of cataracts, and decrease in lens ATP levels. Addition of vitamin E and vitamin E succinate, but not vitamin E acetate, to the diet resulted in reduction of gamma-crystallin leakage into the vitreous humors and an increase in body weight. There was no improvement noted for the lens ATP levels, the general body condition, or visual cataract score. Neither streptozotocin-induced diabetes nor vitamin E in the diet appeared to affect the weight of the lenses.

Endogenous superoxide‐like species and antioxidant activity in ocular tissues detected by luminol luminescence

A new luminescent method was used to detect the reactive oxygen species in aqueous and vitreous humors and in homogenates of the lens and retina of laboratory rats. Superoxide‐like activity per μg protein increased in all tissues with weight of the rat, a good indicator of animal age. Superoxide dismutase, centrophenoxine, soluble vitamin E (D‐α‐tocopherol (polyethlyene glycol 1000) succinate, and N′‐diphenyl‐p‐phenylenediamine (DPPD) reduced the luminescence. Catalase had no effect. These results are consistent with the detected species being superoxide‐like.

Effects of Ginseng Supplementation and Endurance-Exercise in the Artery-Specific Vascular Responsiveness of Diabetic and Sedentary Rats

This study examined the effects of 12 weeks North-American ginseng supplementation, exercise training, and sedentary behavior on vascular responses in type I diabetic rats. The following hypotheses were tested: (1) ginseng supplementation would result in improved vascular responsiveness and sensitivity; (2) exercise training would result in further improvement in these vascular responses; (3) control rats with no access to exercise would show a depressed vascular response compared to control rats that were not exposed to a sedentary lifestyle. Groups: non-diabetic sedentary control (CS), sedentary diabetic (DS), sedentary diabetic with ginseng supplementation (DS+GS), diabetic with ginseng supplementation and high-intensity endurance exercise (D+GS+EX), and control not exposed to sedentary behavior (C). Diabetes was induced by streptozotocin. Arteries were excised, cleaned, and mounted onto a myography system. Percent vasorelaxation to acetylcholine (ACh) (10-8 M ACh to 10-4 M ACh) of the carotid artery was similar in CS (57 ± 31%), C (66 ± 35%), DS (58 ± 36%), D+GS+Ex (71 ± 37%), and DS+GS (64 ± 37%) (p > 0.05). Percent vasorelaxation of the aorta was smaller in CS (23 ± 17%) compared to C (46 ± 35%), DS (60 ± 40%), D+GS+Ex (64 ± 40%), and DS+GS (56 ± 39%) (p < 0.05), and smaller in C compared to D+GS+Ex (p < 0.05). In the femoral, the percent vasorelaxation was reduced in DS (18 ± 16%) compared to all the other conditions (CS, 43 ± 22%; C, 79 ± 28%; D+GS+Ex, 55 ± 27%; DS+GS, 45 ± 26%; p < 0.05), but larger in C compared to the other conditions (CS, DS, D+GS+Ex, DS+GS; p < 0.05). Diabetes and sedentary lifestyle have detrimental effects on vascular responses that are evident in the femoral arteries of the diabetic rats. Ginseng supplementation restored the loss of sensitivity, with no added vascular protection of exercise training.