ABSTRACT

 

 

 The effect of oleanolic acid or vit E on heavy metal (cadmium) -induced thyroid dysfunction and lipid peroxidation in male rats was studied. Materials  and methods:The animals divided into 3 groups each of which 6 rats .The first group  were injected with 1mg/kg/day cadmium  chloride,1% solution in distilled water  subcutaneously daily for 30 days.The second group were injected simultaneously with equivalent dose of cadmium chloride (1mg/kg/day) subcutaneously and oleanolic acid in a dose of 5 mg/kg/day,2% suspension in 2% tween 80 intramuscularly for 30 days.The third group were injected simultaneously with equivalent dose of cadmium chloride (1mg/kg/day) subcutaneously and vit E, in a dose of 100mg/kg (5% solution in saline ) intramuscularly for 30 days.In addition to other three control groups treated with distilled water , tween 80 and saline ,respectively.Results:Cadmium chloride treatment alone led to decrease in concentrations of serum thyroid hormones , zinc and copper concentration (p<0.01) .In addition  , a significant increase in both malondialdyhyde (MDA) levels and thyroid stimulating hormone (TSH) has been observed by Cd-treatment alone (p<0.01).Treatment with either oleanolic acid or vit E improved the metal –induced decrease in serum thyroid function.Treatment with oleanolic acid lead to decrease in levels of  blood and hepatic malondialdyhyde but remain higher than normal rates (47.14±0.82µmol/L and 119±0.86 µmol/g wet tissue, respectively ). However, treatment with Cd and vit E restored blood and hepatic malondialdyhyde levels toward normal values (34.7±0.65µmol/L and 100.4±1.44µmol/g wet tissue, respectively). Conclusion: The effect of vit E combined with cadmium is significant compared with the effect of oleanolic acid treatment with cadmium (p<0.01).The protective effect of each oleanolic acid or vit E against cadmium-induced thyroid dysfunction is mediated through its antioxidative action.