Increasing interest in the role of β-carotene in diseases prevention led us to examine the effects of β-carotene's administration on liver of rats who have diabetes induced by streptozotocin (STZ). 45 adult albino rats, each weighs from 110 to 130 g were divided into six groups. GI: control rats; GII: rats were injected intraperitoneally (i.p) with a single dose of 40 mg streptozotocin to become diabetic and the animals who failed to become diabetic were excluded from the experiment. The already diabetic rats were divided into two groups, GIII & GIV. Rats of these two groups were injected i.p. with 0.3 & 0.1 mg β-carotene respectively, three times/week on alternate days for two months. In GV & GVI: rats were given i.p. the same previous doses of β-carotene only according to the same schedule. Histological and ultrastructural studies were performed on the liver of the control and experimental groups. The liver of the diabetic rats (GII) showed congestion of the blood vessels and dilatation of the sinusoids. The hepatocytes displayed vacuolation, pyknosis of their nuclei, disintegration of mitochondria and decrease in rough endoplasmic reticulum and glycogen. These changes were markedly decreased in the liver tissue of rats of GIII and GIV who were treated with β-carotene. It was observed that β-carotene had retained the normal organization of most of the structural organelles of the hepatocytes. Also, it restored the proper stainability for the hepatocytes nuclei, and helped avoidance of the increased eosinophilia of cytoplasm. In addition, β-carotene had improved the glucose utilization by the increase in glycogen storage in hepatocytes. In summary, treatment of diabetic rats with 0.3 & 0.1 mg β-carotene has beneficial effects on the structure of the diabetic liver tissues induced by STZ. These findings indicate that treatment with the antioxidant β-carotene can protect the liver against diabetes.
Key words: Diabetes Mellitus beta- carotene Streptozotocin oxidative stress antioxidants hepatocytes
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