- 學位論文
以酒精與四氯化碳誘導肝損傷動物模式評估護肝功能之研究
Alcohol- and carbon tetrachloride-induced liver injury as animal models for hepatoprotection evaluation
摘要
本研究提出酒精性肝損傷動物模式，並且以四氯化碳誘導肝損傷之護肝功能評估方法探討其適用性。實驗動物為雄性Wistar大白鼠，體重約160~180g，依照血漿AST與ALT的活性分為五組，包括：對照組 (C)、酒精組 (E)、酒精＋silymarin組 (ES)、四氯化碳組 (CCL)、四氯化碳＋silymarin組 (CCLS)，E與ES組給予Lieber-DeCarli酒精液體飼料，C、CCL與CCLS組則給予正常液體飼料；CCL與CCLS組每週皮下注射四氯化碳一次 (0.75 mL 40％CCl4 in olive oil/kg BW)，C、E與ES組則週皮下注射橄欖油一次 (0.75 mL olive oil/kg BW)；ES與CCLS組另外在飼料中添加silymarin，200 mg/kg BW。實驗期為12週。結果顯示，實驗期間血漿AST與ALT活性方面，E、ES、CCL與CCLS組皆較C組顯著增加，第12週時，CCLS組較CCL組顯著減少。在相對肝重方面，E、ES、CCL與CCLS組皆較C組顯著增加，而silymarin可以改善因酒精或四氯化碳造成相對肝重增加的情形。紅血球抗氧化酵素活性方面，CCLS組之superoxide dismutase (SOD)與glutathione peroxidese (GPX)的活性與C組比較顯著增加，E與ES組之catalase (CAT)活性與C組比較顯著增加，而CCL與CCLS組之glutathione reductase (GRD)活性則比C組顯著增加。肝臟抗氧化酵素活性方面，與C組比較之下，E、ES、CCL與CCLS組之SOD與GPX活性顯著降低，CCL組之GRD活性顯著降低，CCL與CCLS組之CAT活性顯著降低。肝臟抗氧化物質GSH/GSSG比值方面，E、ES、CCL與CCLS組皆顯著較C組減少，CCL組又顯著較E組減少，而給予silymarin皆可以改善因酒精或四氯化碳造成肝臟GSH/GSSG比值減少的情形。肝臟維生素E含量方面，E、ES、CCL與CCLS組皆顯著較C組減少，CCL組又較E組減少。肝臟脂質過氧化物thiobarbituric acid reactive substances (TBARS)濃度方面，E、ES、CCL與CCLS組與C組比較顯著增加。血漿脂質濃度的結果，在total cholesterol (TC)與high density lipoprotein-cholesterol (HDL-C)濃度方面，E與ES組顯著較C組增加，CCL與CCLS組則顯著較C組減少，而給予silymarin可以改善因為四氯化碳造成血漿TC減少的情形；在triglyceride (TG)濃度方面，E、ES、CCL與CCLS組皆顯著較C組增加；各組之血漿low density lipoprotein-cholesterol (LDL-C)濃度皆無顯著差異。肝臟TC、TG含量方面，E、ES、CCL與CCLS組較C組顯著增加，CCL組又較E組顯著增加。發炎指標myeloperoxidas (MPO)活性方面，E、ES、CCL與CCLS組與C組比較皆顯著增加，而四氯化碳較酒精的影響更為顯著。肝臟病理切片分析方面，E、ES組肝臟有脂肪堆積的情形，CCL、CCLS組除了脂肪堆積，另有細胞壞死、發炎與纖維化的情形，而給予silymarin皆可以減少脂肪堆積的情形。研究顯示，相較於四氯化碳，長期攝取酒精所誘導之大白鼠肝損傷程度較輕微，給予silymarin可以增加肝臟抗氧化物質進而降低肝臟傷害。本研究所使用之酒精性肝損傷動物模式，可誘導大白鼠形成脂肪肝，將來可作為預防或降低酒精性肝損傷的健康食品檢測模式。
並列摘要
In this study, we examined the applicability of an animal model for the alcohol-induced liver injury in hepatoprotective evaluation. According to both the plasma AST and ALT activities, 50 male Wistar rats were assigned to five groups: C (control feeding), E (ethanol feeding), ES (ethanol feeding combined with the supplementation of silymarin, 200 mg/kg BW/day), CCL (CCl4 injection and control feeding) and CCLS (CCl4 injection and control feeding combined with the supplementation of silymarin, 200 mg/kg BW/day). Rats were fed for 12 weeks on a control or an ethanol Lieber-DeCarli liquid diet. Rats in groups CCL and CCLS were intraperitoneally injected with 0.75 mL/kg BW of 40% CCl4 dissolved in olive oil once a week, while rats in groups C, E and ES were intraperitoneally injected with 0.75 mL/kg BW of olive oil only. Our dada indicated significant main effects of both ethanol feeding and carbon tetrachloride injection on increased relative liver weight (%); elevated plasma AST and ALT activities at weeks 2, 4, 6, 8, 10 and 12; lowered plasma TG concentrations at week 12; increased hepatic TG and TC contents; elevated hepatic MPO activity; increased plasma TBARS concentrations at week 12; increased hepatic TBARS level; reduced hepatic GSH/GSSG ratio; decreased hepatic vitamin E level; decreased hepatic antioxidant enzymes, GPX and SOD activities; and pathologically changed liver; when compared to control feeding. Moreover, after 12 weeks, the results also showed significant main effects of carbon tetrachloride injection on increased relative liver weight (%); elevated plasma AST and ALT activities; reduced all the plasma TG, TC and HDL-C concentrations; augmented hepatic TG and TC contents; elevated hepatic MPO activities; increased plasma TBARS concentration; reduced hepatic GSH/GSSG ratio; decreased vitamin E level; decreased hepatic antioxidant enzymes, GRD and CAT activities; and severe fatty change in livers; when compared to ethanol feeding. In rats fed an ethanol liquid diet, silymarin could improve relative liver weight, hepatic GSH/GSSG ratio, plasma TBARS concentration and liver fatty change; and in rats injected carbon tetrachloride, silymarin could improve plasma AST and ALT activities at week 12, plasma TC concentration, hepatic GSH/GSSG ratio, and liver fatty change. In conclusion, our results suggest that both long-term ethanol feeding and carbon tetrachloride injection significantly increased oxidative stress, lipid peroxidation, and decreases the ratio of GSH/GSSG in rats, and ethanol feeding induced a slight susceptibility to liver damage than carbon tetrachloride injection. Silymarin showed the hepatoprotective effects by means of improving the antioxidative capacity treatment protected against ethanol or carbon tetrachloride induced liver damage. The animal model for the alcohol-induced liver injury in this study provided a technically simple way to reproduce early stages of alcohol liver disease, and could be a hepatoprotective evaluation in preventing alcohol liver disease.