Abstract: BACKGROUND ＆ AIM: To study the inhibitory effect of grape procyanidin(GPC) on the mutagenicity of N-nitroso compounds. MATERIAL AND METHODS: Wistar rats were given 0.5 ％ NaNO2 to induce hepatocytes′ mutation,and GPC was given by 100 and 10 mg/kg respectively through mouths into the rats of the two experimental groups at the same time. After eight weeks, rats were killed and immunohistochemistry method was applied to measure the expression level of mutant P53 protein in rats′ hepatic cells , and bone marrow micronucleus method was applied to measure the rate of bone marrow micronucleus.RESULTS: The number of positive cells of mutant P53 protein expressed in the induced-injury group was 84.95 ± 6.33,and the rate of bone marrow micronucleus was 37.40 ‰,and those of the high-dose GPC group were 16.30±1.63 and 8.40 ‰ and the low-dose GPC group were 57.50±4.68 and 24.20 ‰. The ifferences between the two GPC groups and the induced-injury group had statistical significance(P<0.01). CONCLUSION: GPC can decrease the expression level of mutant P53 protein and the rate of bone marrow micronucleus induced by NaNO2 ,and it has an inhibitory effect on mutagenicity of N-nitroso compounds.

Key words: grape procyanidin, hepatocytes, P53 protein, N-nitroso compounds