Effects of Melatonin and Aminoguanidin on Liver Induced by Manganese in Rat

Objective To observe effects of melatonin(MLT)and aminoguanidin(AG)on liver induced by Mn through measuring NO,MDA levels and iNOS activity.Methods 40 SD rats were randomly divided into four groups by weight.The first group was the control group which was intraperitoneally(i.p.)injected with 0.9% NaCl only.The second group was i.p.injected with 0.9% NaCl.The third and fourth groups were respectively i.p.injected with MLT 5 mg/kg and AG 40 mg/kg.After two hour,the first group was given subcutaneous(s.c.)injection of 0.9% NaCl.The second to fourth groups were given s.c.injection of 200 μmol/kg MnCl2.4 weeks after administration,the rats were anatomized and their liver tissue samples and blood serum were collected.The LDH and GPT activities in blood serum,the activity of iNOS and the levels of NO and MDA in liver were determined.Results 4 weeks after administration,the results showed that compared with the control group the LDH and GPT activities in blood serum,the activity of iNOS,the levels of NO and MDA in liver of the MnCl2-exposed rats increased significantly.Compared with the MnCl2-exposed rats the LDH and GPT activities in blood serum,the activity of iNOS and the levels of NO and MDA in liver decreased significantly in the MLT and AG group.Conclusions Manganese-induced hepatotoxicity is related to the increase of NO and MDA levels and iNOS activity.To some extent,MLT and AG could prevent manganese-induced hepatotoxicity.

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