【作者】 谢卫兵；

【导师】 周天鸿；

【作者基本信息】 暨南大学 ， 医学遗传学， 2001， 硕士

【摘要】 妊娠高血压综合征（PIH）是严重危害孕产妇和待产儿健康的疾病之一，但是其发病机制至今仍未弄清楚。NO是体内最强的血管舒张因子，目前普遍认为内源性NO产量的减少可能是导致妊高征发生的重要原因之一。体内满足生理功能所需要的NO主要由内皮型一氧化氮合酶（eNOS）催化L-精氨酸生成瓜氨酸与NO的反应提供，并且eNOS是该反应途径中唯一的限速酶。妊高征患者体内NO合成量的减少可能是由于eNOS基因突变所致。故人们推测eNOS基因可能是妊高征的易感基因。位于eNOS基因外显子7上G894T突变导致其编码蛋白298位发生Glu/Asp的错义突变，该突变存在影响eNOS蛋白的稳定性，从而降低蛋白的催化活性。另外位于eNOS基因启动子上T-786C突变能显著降低该启动子的转录活性，从而减少eNOS蛋白的合成，NO合成量也随之减少。为证实这两个多态性是否同样在中国人群中存在以及频率分布情况，并判定是否是妊高征发病的风险因子。我们以中国人群（包括妊高征患者组、正常妊娠组、随机妇女组及随机人群组）为研究对象，分别用PCR-RFLP和PCR-SSCP与测序和PCR-TGGE的方法检测了eNOS基因G894T和T-786C这两个多态性位点的存在并统计各自的频率分布。结果在51例中、重度妊高征患者和56例正常妊娠者、74例随机妇女以及82例随机人群中外显子7突变基因型（GT，TT）频率分别为35.4％、31.1％、26.8％、27.5％（P=0.751），T基因频率分别为18.3％、15.5％、13.4％、13.7％（P=0.661）；同时在55例中、重度妊高征患者和82例正常妊娠以及96例随机妇女中启动子突变基因型（CC，TC）频率分别为19.8％、15.9％、20％（P=0.951），C等位基因的频率分别为10.9％、9.0％、11.8％（P=0.755）。因此，在中国人群中存在外显子7 G894T和启动子T-786C这两个多态性位点。应用病例-对照分析的方法分析了这两个多态性与中、重度妊高征的相关性。结果发现这两个多态性位点均与中、重度妊高征不相关。我们未能找到eNOS基因是妊高征的候选基因的直接证据。eNOS基因是否是妊高征的易感基因还需进一步实验证明。更多还原

【Abstract】 Pregnancy induced hypertension (PIH) is one of severe diseases which badly endanger the health of pregnancy woman and fetus. Genetic factors appear to be important in pathogenesis of PIH, but the molecular basis of this genetic predisposition remains largely unknown. Vascular endothelial cells produce nitric oxide (NO), a vascular smooth muscle relaxing factor which plays an important role in the regulation of blood pressure and regional blood flow. NO is produced by endothelial nitric oxide synthase (eNOS) from L梐rginine, eNOS is only key synthase in this pathway. A large number of studies have shown that decreasing of NO is contributed to development of PIH. The mutation of eNOS gene resulted in decreasing of NO produce within PIH woman. So eNOS gene may be the candidate gene for PIH. A variant within exon 7 of eNOS gene: G to T conversion at nucleotide position 894 resulting in replacement of glutainic acid aspartic acide at condon 298 effects the stability of eNOS protein and results in decreasing of NO produce. Another variant within promoter of eNOS gene: T to C conversion at nucleotide position ?86 results in reducing promoter activity by ~5O% and impairs NO biosynthesis. To explore this two variants of eNOS gene, and to analysis the relationship between the eNOS 3 gene and PIH women in Chinese population, polymerase chain reaction 梤estriction fragment length polymorphism (PCR桼FLP) analysis was used to screen the variant G8941 in exon7 of eNOS gene in PIH and normotensive pregnancy women and random women and random people subjects; polymerase chain reaction single strand conformation polymorphism (PCR桽SCP) with PCR direct梥equencing analysis and polymerase chain reaction 梩emperature gradient gel electophersis (PCR桾GGE) analysis were used to screen the variant T?86C in promoter of eNOS gene in PIH and normotensive pregnancy women and random women subjects. The frequencies of variants (GT, TT) of exon 7 on 51 middle, server PIH women and 56 normotensive pregnancy women and 74 random women and 82 random peoples subjects were 35. 4%, 31. 1%, 26. 8%, 27. 5%, respectively. There were no statistical different in gene type of variants (GG, TI) of exon 7 among them (P0. 751). The I allele frequencies of exon 7 in middle, server PIH was 18. 3%, in normotensive pregnancy women was 15. 5%, in random women was 13. 4%, and in random peoples was 13. 7%. There were also no statistical different in I allele of eNOS gene exon7 among them (P0. 661). Another, the frequencies of variants (IC, CC) of promoter on 55 middle, server PJH women and 82 normotensive pregnancy women and 96 random women subjects were 19.8%, 15.9%, 20%, respectively. There were no statistical different in gene type of variants (IC, CC) of promoter of eNOS gene among them (P0. 951). The C allele frequencies of promoter in middle, server PIH was 10. 9%, in normotensive pregnancy women was 9.0%, and in random women was 11.8%. There were also no statistical different in C allele of promoter of eNOS gene among them (P0. 775). The results do not suggest that G894T in exon7 and I?86C in promoter of the eNOS gene are involved in development of PIH. Further work must to be done to seek evidence 4 for association be更多还原