叶酸、核黄素及MTHFR C677T多态性对人淋巴细胞遗传稳定性的影响

目的:探讨叶酸、核黄素及MTHFR C677T多态性对人淋巴细胞遗传稳定性的综合影响。方法:利用胞质分裂阻断微核技术分析了叶酸(20、200nmol/L即LF、HF)和核黄素(1、500nmol/L即LR、HR)不同浓度组合以及MTHFR C677T多态性对9d培养的人淋巴细胞基因组稳定性的影响。结果:对于任何MTHFRC677T基因型,LFHR组的遗传损伤程度居所有浓度组合之首,而HFLR组则最低(P<0.05),高叶酸条件下的微核化双核细胞(micronucleated binucleated cell,MNedBNC)、核芽(nuclear bud,BUD)和核质桥(neacleo plasmic bridge,NPB)频率分别是低叶酸浓度的34.9%、30.6%和35.5%;高核黄素条件下的遗传损伤频率约比低核黄素高7.0%～12.7%;MTHFR677CC基因型遗传稳定性显著高于突变纯合子677TT(P<0.01);叶酸对MNedBNC、BUD、NPB的变异贡献率分别达到71.1%、69.0%和68.2%(P<0.001);核黄素对BUD、MTHFR C677T多态性对MNedBNC和BUD的变异贡献虽达到显著水平,但均不及叶酸;叶酸、核黄素和MTHFR C677T基因型之间的交互作用对基因组稳定性没有显著影响。结论:叶酸、核黄素和MTHFR C677T多态性以不同程度影响基因组稳定性,其中叶酸是本实验条件下影响基因组稳定性的最主要因素。

THE IMPACTS OF FOLIC ACID, RIBOFLAVIN AND MTHFR C677T POLYMORPHISM ON HUMAN LYMPHOCYTES GENOMIC STABILITY

Objective: To explore the comprehensive effects of folic acid (FA), riboflavin (RF) and MTHFR C677T polymorphism on genomic stability. Method: Cytokinesis-block micronucleus assay was used to detect the effects of different concentration combination of FA (20 and 200nmol/L, i.e. LF and HF) , RF (1 and 500 nmol/L, i.e. LR and HR) and MTHFR C677T polymorphism on genomic stability of 9 d cultured human lymphocytes. Results: The genetic damage was significantly higher in LFHR group regardless the genotype (P<0.05). The highest level of genomic stability was found in all HFLR groups. The levels of MNed BNC, BUD and NPB were 34.9%、30.6% and 35.5% lower in HF groups compared with those in LF groups. However, those biomarker frequencies were 7.0-12.7% lower in LR groups than in HR groups. FA concentration accounted for 71.1%、69.0% and 68.19% of the variation of MNed BNC, BUD and NPB levels, respectively. RF showed significant contribution on BUD variation and genotype showed the same contribution on MNed BNC and BUD level but the effects were relatively small compared with that ofFA. No interactions among FA, RF and genotypes on the genomic stability were found. Conclusion: MTHFR C677T and RF affect genomic stability, however, the effect is relatively small compared with that of FA. FA is the most important determinant of genomic stability in our present study.