| Summary: | 碩士 === 台北醫學院 === 保健營養學研究所 === 89 === The purpose of this study was to investigate the effects of β-carotene on alcoholic liver diseases in rats. In vitro study was to evaluate the effects of β-carotene on the cell viability and antioxidant enzymes activities in hepatocytes from rats with alcoholic liver disease (ALD). Rats in ethanol group were given ethanol-containing diet (powdered- ethanol 58g per 100g diet), and rats in control group were fed isocaloric diet without ethanol. After 10 weeks, rats in ethanol group showed a significant increase in plasma GOT and GPT activities by 24% and 61%, respectively. Furthermore, the apparent accumulation of fat within hepatocytes was observed in ethanol group. Then, the hepatocytes were taken out and cultured for 24 hrs. Hepatocytes from control group were cultured in the medium without (HC) or with b-carotene (HC+B), and from ethanol group were also cultured in the medium without (HE) or with β-carotene (HE+B). Results showed that lactate dehydrogenase leakage (LDH leakage), which is the index of cell viability, was significantly increased by 68% in HE than in HC, but reduced by 42% in HE+B than in HE. When compared to HC, the activities of glutathione peroxidase (GPX) and catalase (CAT) in HE were significantly decreased by 54% and 31%, respectively. CAT activity in HE+B group was significantly increased by 61% than in HE. However, the activities of glutathione reductase (GRD) and superoxide dismutase (SOD) showed no difference in each group. The levels of glutathione (GSH) in HC+B and HE+B groups were significantly increased 155% and 143% than in HC and HE, respectively. The concentration of lipid peroxidation products malondialdehyde (MDA), showed no difference in each group. On the other hand, the cellular levels of β-carotene and retinol were significantly increased in HC+B and HE+B. And the levels of b-carotene and retinol in medium increased in HC+B and HE+B. These results demonstrate that β-carotene can increase cell viability, CAT activities, GSH, β-carotene and retinol concentrations in cultured hepatocytes from rats with ALD.
In vivo study was to investigate the effects of β-carotene on antioxidant enzyme activities, lipid metabolism, and hyperuricemia in rats with ALD. Rats were divided into three groups, such as control (C), ethanol (E) and ethanol with β-carotene (E+B) groups. Rats in E group were given ethanol-containing diet (58%), in E+B group rats were fed ethanol-containing diet with β-carotene, and rats in C group were fed isoenergetic diet without ethanol or b-carotene. After 10 weeks, results revealed that plasma GOT and GPT activities in E group were significantly increased by 25% and 27% respectively than in C group. When compared to E group, plasma GOT and GPT activities in E+B group were significantly decreased by 12% and 15% respectively. The activities of erythrocyte GPX, GRD, SOD and CAT showed no difference in each group. Additionally, hepatic GPX activity in E group was significantly decreased by 21% than in C group. Hepatic CAT activity in E group was significantly increased by 27% than in C group, whereas it was significantly decreased by 20% in E+B group than in C group. The activities of GRD and SOD in liver showed no difference in each group. When compared with C group, the concentration of GSH was significantly decreased by 15% in erythrocyte and 23% in liver of E group. In E+B group, GSH content in erythrocyte and liver were significantly increased by 43% and 27% respectively than in E group. The level of MDA in erythrocyte and liver showed no difference in each group. β-carotene storage was detected in liver of E+B group. The hepatic retinol content was significantly increased by 51% in E+B group than in E group. Plasma triglyceride (TG) concentration in E group was significantly increased by 27% and 96% respectively than in C group. And the hepatic TG and total cholesterol (TC) contents in E group were significantly increased by 73% and 33% respectively than in C group. However, in E+B group, plasma TG and hepatic TG, TC levels were significantly lowered 40% and 38%, 20% respectively than in E group. Besides, both plasma TC and high-density lipoprotein cholesterol (HDL-C) concentrations were significantly increased 13% in E+B group than in E group. The level of plasma uric acid in E group was significantly increased by 50% than in C group, but it was significantly decreased by 30% in E+B group than in E group. Furthermore, the apparent accumulation of fat within hepatocytes was observed in ethanol group. Results demonstrate that b-carotene supplementation could prevent alcoholic liver diseases formation by enhancing antioxidant capacity, decreasing the plasma TG concentration, and inhibiting the
accumulation of TC and TG in liver.
Key words：β-carotene、alcoholic liver diseases、hepatocytes、rats.
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