The Effects Of PC-B2 On DNA Oxidative Damage And Ralated Gene Expression In AFB₁- Exposured L-02 Cells

ObjectiveProcyanidin B2 with biological functions of scavenging free radicals, anti-cancer and so on is a polyphenol compound widely exists in plant. Aflatoxin B1 is a common kind of mycotoxin in areas with high temperature and high humidity. AFB1 can result in acute and chronic liver cell damage. Epidemiology studies have shown that AFB1 is significantly related with human hepatic carcinoma, its mechanism may be related to AFB1 metabolites and oxidative damage caused by free radicals. Study about effects of PC-B2 on the liver cell DNA oxidative damage caused by AFB1 is less.This article was to explore the effect PC-B2 on AFB1 caused hepatocyte DNA oxidative damage and its possible mechanisms. Provide theoretical and experimental basis for the reasonable application of procyanidins in prevention and treatment of AFB1 related liver disease to provide theoretical and experimental basis.MethodsWell-cultured and in logarithmic growth phase cells were divided into 5 groups:(1)control group：cells were cultured in complete medium; (2)DMSO group：cells were cultured with DMSO; (3)AFB1 exposure group：cells were cultured with AFB1; (4)PC-B2 exposure groups:cells were cultured with PC-B2; (5) PC-B2 intervention groups:cells were cultured with both PC-B2 and AFB1. The cell proliferation and the levels of cellular 8-OHdG and related genes expression were assayed by 3-(4,5-dimethylthiazolyl)- 2,5-diphenyltetrazolium bromide (MTT) method、ELISA method and qPCR method.Results1.The cell proliferation in AFB1 exposure groups were significantly inhibited and showed a dose-effect relationship in the concentration of the range from 100μg/ml to 40μg/ml(P<0.05), and it was 69.9% in the 30μg/ml AFB1 exposure groups,which was used for the infection concentration. Concentration range from 5μg/ml to 75μg/ml,PC-B2 help to stimulate cells’growth, and 25μg/ml PC-B2 showde the best effect. When the PC-B2 concentration reached 100μg/ml,it showed a inhibiting effect. So we choose 3、10、30μg/ml as the concentration of PC-B2 for the further test. Compared with 30μg/ml AFB1 exposure group, the cell proliferation were increased in PC-B2 intervention groups(P<0.05).2.Compared with DMSO group[(0.580±0.045)ng/ml], the content of 8-OHdG[(2.779±0.089)ng/ml] was significantly increased in 30μg/ml AFB1 exposure group(P<0.05). Compared with 30μg/ml AFB1 exposure group, the contents of 8-OHdG[(2.550±0.078)、(2.376±0.109)、(1.873±0.065)ng/ml] were significantly decreased in PC-B2 intervention groups(P<0.05).3.The expression of hOGG1 decreased (as 0.55 times as the DMSO group) in the 30μg/ml AFB1 group, but it obviously increased after the intervention of PC-B2(P<0.05).4.AFB1 infected cells the Bcl-2/bax ratio is relatively lower than teh control and DMSO group, PC-B2 intervention group were higher than that of AFB1 infected group.ConclusionPC-B2 in the certain concentration range help to stimulate the growth of L-02 liver cells, but has cytotoxicity in a high dose.PC-B2 has the effect of inhibiting hepatocyte damage,it may ralated to its regulation on repaire-gene expression and antagonism on DNA damage. The function of Bcl-2 and bax need for further research.