D-limonene Improves The Experimental Study Of Alcoholic Liver Injury In Rats

Objective: To observe the effects of D-limonene on the antioxidant ability and the expression of NF-?B and COX-2 in liver in rats of alcohol-induced hepatic injury.Methods: 70 male Wistar rats were randomly divided into the following seven groups. Group A was the control group; Group B was ethanol-treated group with 50%(v/v) ethanol 8 m L kg-1day-1 for 2 weeks following by an increasing intake of ethanol up to 12 m L kg-1day-1for the remaining 4 weeks; C, D, E groups were low, medium and high dose D-limonene[100, 200, and 400 mg/(kg?d)]groups; Group F was high dose D-limonene group with 400 mg/kg D-limonene per day; G group was diammonium glycyrrhizinate group with 200mg/(kg?d) diammonium glycyrrhizinate. The ethanol dose of C, D, E, G group was equal with ethanol-treated group, and distilled water dose of group F was equal with the control group. Each group of 10 and experiment last for 6 weeks. After the last lavage, food was prohibited with all rats for 12 h, anesthesia, abdominal aortic blood serum and liver tissue specimens were separated. Liver histopathology were obtained by HE staining. The total superoxide dismutase(SOD), malondialdehyde(MDA),and glutathione peroxidase(GSH-Px) were detected. The expression of NF-?B and COX-2 in liver was detected by immunohistochemistry.Results: Pathological observation of liver tissue by HE staining showed the liver tissue of ethanol-treated group was bullous steatosis and there was a large number of inflammatory cell infiltration. steatosis were different degree of diminution and inflammatory cells were decreased in each dose D-limonene than ethanol-treated group. Compared with control group, plasma SOD and plasma and liver homogenates GSH-Px were decreased in the ethanol-treated group.Plasma and liver homogenates MDA were increased(P<0.05); compared with ethanol-treated group, medium and high dose D-limonene plasma SOD and each dose D-limonene plasma and liver homogenates GSH-Px were increased. Plasma and liver homogenates MDA were decreased(P<0.05). The NF-?B and COX-2 expressions in Ethanol-treated group were increased with comparison of control group, and the expressions of NF-?B and COX-2 were decreased with comparison of ethanol-treated group(P<0.05). Compared with the control group, each index of group F has no obvious difference in rats(P>0.05).Conclusion: D-limonene may enhance the activity of antioxidant enzymes and reduce lipid peroxidation products,and reduce expression of NF-?B and COX-2, thus D-limonene can improve liver damage caused by alcohol exposure.