MTHFR基因多态性对血管内皮功能指标的影响

目的：研究社区人群中MTHFR 677C→T基因突变对血管紧张素Ⅱ、前列环素和一氧化氮水平的影响。方法：整群抽取社区汉族成年居民1 146人，采用PCR－RFLP鉴定目标人群MTHFR 677位基因型；采用荧光生化技术测定血浆Hcy浓度；用镉还原法检测其血清一氧化氮水平，用放射免疫分析法检测血浆血管紧张素Ⅱ和前列环素的浓度。所有数据用SPSS 13.0 软件进行统计分析。结果：1 146例居民按MTHFR 677基因型自然分组，三组之间PGI₂、AngⅡ没有统计学差异；C/C和T/C基因型组之间血清NO水平无显著差异（P>0.05），T/T基因型组的血清NO水平较C/C和T/C基因型组都低（P＜0.01）。结论:社区人群中MTHFR 677C→T突变对血浆PGI₂、AngⅡ的影响并不明显；血清NO水平下降，可能是MTHFR 677C→T导致缺血性心脑血管病的机制之一。

Influence of MTHFR genetic polymorphism on the indexes of vascular endothelial functions

AIM: To investigate the influence of methylenetetrahydrofolate reductase (MTHFR) 677 C→T mutation on angiotensin Ⅱ (Ang II), prostacyclin (PGI₂) and nitric oxide (NO). METHODS: By cluster sampling, 1146 adult Han people were selected from the residential communities. MTHFR 677 genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism for each sample. Plasma levels of homocysteine were determined by fluorescence ration biochemical assay. Serum NO levels were determined by cadmium reduction method. Plasma AngⅡ and PGI₂ concentrations were determined by radioimmunoassay. SPSS 13.0 was used for data analysis. RESULTS: Total samples were divided into three groups according to the genotypes. No significant difference in PGI₂ and AngⅡamong the three groups was observed. The difference of serum NO level between the C/C and T/C genotypes was not significant (P>0.05). The serum concentration of NO of T/T genotype was significantly lower than that of T/C and C/C genotypes (P<0.01). CONCLUSION: The influence of MTHFR 677 C→T mutation on Ang II and PGI₂ is not significant in the people from the residential communities. The decrease in serum NO level might be one of the underlying mechanisms of MTHFR 677 C→T mutation causing myocardial infarction and ischemic stroke.