Modulation of Nitrosamine-Induced Liver Injury in Rats by Propolis Extract: Long-term Study

This study investigated the prophylactic effect of propolis extract against nitrosamine-induced liver injury in experimental animals. Eighty male adult rats were grouped into 8; control, treated with propolis extract, 3 groups treated with 0.1, 0.2, 0.5 mg nitrosamine/kg b.w and 3 groups treated with nitrosamine plus 2.5 mg/kg propolis extract for 12 weeks. Data obtained showed that, propolis extract exert prophylactic activity against nitrosamine-induced hepatotoxicity. Administration of nitrosamine lead to, liver function tests, oxidative stress markers and inflammatory markers were significantly increased. Propolis extract administration resulted in normalizing of the elevated liver functions. The propolis extract lowered the oxidative stress and the inflammatory markers compared with untreated group. In addition, histological investigation of livers revealed that propolis extract reduced lymph infiltration, hepatic congestion and inflammation in nitrosamine-injected rats. It was deduced that, the propolis extract exert hepatoprotective effect against liver damage induced by nitrosamine and it possess anti-inflammatory action.