EFFECTS OF D-LIMONENE ON ANTIOXIDANT ABILITY AND THE EXPRESSIONS OF NF-κB AND COX-2 IN RATS WITH ALCOHOL-INDUCED HEPATIC INJURY

Objective To observe the effects of D-limonene on antioxidant ability and the expressions of NF-κB and COX-2in liver of rats with alcohol-induced hepatic injury. Methods Seventy male Wistar rats were evenly randomized to seven groups as A,B,C,D,E,F and G-according to body weight.Group A was the control group;Group B was ethanol-treated group,the rats in this group were given 50%(V/V)ethanol 8mL·kg-1·d-1 for 2weeks following by increasing intake of ethanol up to12mL·kg-1·d-1 for the remaining 4weeks;for groups C,D and E,low,medium and high dose D-limonene(100,200,and400mg/(kg·d))was given,respectively;those in group F were offered water and high dose D-limonene(400mg/kg),intragastrically;those in group G was intragastric administration of diammonium glycyrrhizinate 200mg/(kg·d)same time as ethanol was given,once a day.The experiment lasted for six weeks.After the last intragastric administration,food was prohibited for 12 hours,the blood and liver samples were taken.The pathology of liver tissue was observed by HE staining.the total superoxide dismutase(SOD),malondialdehyde(MDA),and glutathione peroxidase(GSH-Px)were detected.The expressions of NF-κB and COX-2in the liver was detected by immunohistochemical mehod. Results In group B,macrosteatosis and infiltration of a great quantity of inflammatory cells could be seen in the liver tissue;compared with group B,fatty degeneration in group E was lighten,and the number of inflammatory cells decreased.Compared with A group,plasma SOD and plasma and liver homogenate GSH-Px vitality in group B decreased,and the content of MDA in plasma and in liver homogenate increased.Compared with group B,the plasma SOD in groups D and E,and vitality of homogenate GSH-Px in groups C,D and E were higher,and the content of MDA in plasma and liver homogenate was lower(F=42.93-84.37,t=2.73-154.63,P0.05).The expressions of NF-κB and COX-2in group B were higher than that in group A,and in group E,the expressions of both NF-κB and COX-2were lower than that in group B(F=60.38,49.76;t=9.93-15.25;P0.05).A comparison between group F and group A showed no significant differences in terms of each parameter(P0.05).The differences between groups A and F were not significant in terms of each marker(P0.05). Conclusion D-limonene can enhance the activity of antioxidant enzymes in rats with alcohol-induced hepatic injury,reduce production of lipid peroxide and expressions of NF-κB and COX-2in liver tissue,and thus improve liver damage caused by alcohol exposure.