【作者】 李竹；

【导师】 陈莉明； 郭刚；

【作者基本信息】 天津医科大学 ， 内科学， 2007， 硕士

【摘要】 目的：小肠脂肪酸结合蛋白(FABP2)是由小肠简单柱状上皮细胞分泌的一种蛋白质，具有将长链脂肪酸从细胞膜转运至内质网的功能。人类FABP2基因存在多个位点多态性，外显子(exon)2中第54位上鸟嘌呤(G)和腺嘌呤(A)的置换会引起结合脂肪酸的能力的变化。该位点多态性与胰岛素抵抗、2型糖尿病及其并发症的发生密切相关。本文随机300例2型糖尿病患者为糖尿病组和80例无糖尿病对照组(糖耐量正常)为研究对象，测定FABP2基因编码区exon2第54位点的基因型，以便了解FABP2 54基因型多态性与2型糖尿病肾病的关系。方法：收集2型糖尿病患者及健康查体的无糖尿病对照者的空腹外周血标本，全血用于提取基因组DNA，血清用于检测生化指标。应用聚合酶链反应-限制性片段长度多态性分析法(PCR-PFLP)测定300例2型糖尿病患者和80例正常对照者的FABP2 54位点基因型。采用重组DNA技术对目的基因进行测序，应用比色法以及ELISA法测定血清游离脂肪酸(FFA)和血清脂联素(adiponcctin)水平。应用SPSS13.0软件对临床资料进行统计分析。结果：(1)天津地区汉族存在FABP2 Ala54Thr多态性，可产生多态性片段：野生型FABP2 54Ala／Ala；突变型FABP2 54Ala／Thr、Thr／Thr；基因变异频率符合Hardy-Weinberg遗传平衡定律(P＞0.05)。(2)在2型糖尿病组突变型FABP2 54Ala／Thr、Thr／Thr基因型频率与Thr等位基因频率显著高于无糖尿病对照组(P＜0.05)。(3)2型糖尿病组FABP2突变型54Ala／Thr、Thr／Thr基因型患者的空腹血浆甘油三酯(TG)水平和空腹游离脂肪酸(EVA)水平显著高于FABP2野生型Ala／Ala基因型患者(P＜0.05)。(4)2型糖尿病各组中FABP2突变型54Ala／Thr、Thr／Thr基因型患者的胰岛素抵抗指数显著高于各组FABP2野生型54 Ala／Ala基因类型患者(P＜0.05)。(5)天津地区2型糖尿病合并肾病各组FABP2突变型54Ala／Thr、Thr／Thr基因型频率与Thr等位基因频率显著高于正常对照组和2型糖尿病正常白蛋白尿组(P＜0.05)(6)FABP2 54Thr基因型是2型糖尿病合并肾病的独立危险因素，(P＜0.05)。(7)糖尿病肾病组血清脂联素水平显著高于糖尿病正常蛋白尿组(P＜0.05)；2型糖尿病组FABP2突变型54 Ala／Thr和Thr／Thr基因类型患者的空腹血清脂联素水平显著低于FABP2野生型Ala／Ala基因型患者(P＜0.05)。结论：(1)天津地区汉族人存在FABP2基因多态性，基因变异频率符合Hardy-Weinberg遗传平衡定律，提示样本具有群体代表性。(2)FABP2基因多态性可能是2型糖尿病发生的遗传易感因素。(3)FABP2基因多态性是2型糖尿病患者脂质代谢异常的影响因素。(4)FABP2基因多态性与2型糖尿病胰岛素抵抗有关。(5)FABP2基因多态性是涉及2型糖尿病肾病发生的遗传易感因素；携带FABP2基因突变型Ala／Thr和Thr／Thr的个体发生2型糖尿病肾病的风险增高。更多还原

【Abstract】 Objective: The human intestinal fatty acid binding protein (FABP2) isexcreted only from the absorptive simple columnar epithelial cells of the small intestine and ittransports long-chain fatty acids from the plasma membrane to the endoplasmic reticulum. TheFABP2 gene which G for A substitution in codon 54 of exon 2 can alter the ability ofbinding fatty acid. This polymorphism is close correlated with insulin resistance, type2 DM and its complications. The aim of this study is to investigate the prevalence ofthe polymorphism and explore the relation of FABP2 gene variation with type 2diabetic nephropathy.Methods: After an overnight fast, all subjects’venous blood was drawn forDNA extraction and for measuring some biochemistry parameters. Using PCR-RFLPdetecting the 54 A/T polymorphism in exon2 of FABP2 gene. And then, this genewas cloned so as to sequence the polymorphism of the FABP2 gene. We useindependently colorimetric method and ELASA method to determine the fasting FFAand adiponectin.Results:(1) G for A substitution in FABP2 codon 54 of exon 2 results in thesubstitution of threonine(Thr) for alanine(Ala).(2)The frequence of genotype Ala/Thr&Thr/Thr and Thr allel significantly increased in type 2 DM as compared with that innormally control(P＜0.05). (3)The patients with type 2 DM who carry Ala/Thr andThr/Thr genotype had a significantly higher level of fasting plasma TG(P＜0.05) andfasting FFA(P＜0.05) than those with wild-type. (4) The patients with type 2 DM whocarry Ala/Thr and Thr/Thr genotype had a significantly higher level of insulinresistance index than those with wild-type. (5)The frequence of genotype Ala/Thr andThr/Thr significantly increased in diabetic nephropathy as compared with that innormally control and type 2 DM without nephropathy(P＜0.05) (6) FABP2 Thr54 genotype is independent risk factor, (P＜0.05). (7) The serum adiponectin levels aremarkedly increased in diabetic nephropathy than diabetes without nephropathy ; Thepatients with type 2 DM who carry Ala/Thr and Thr/Thr genotype had a significantlylower level of serum adiponectin (P＜0.05) than those with wild-type.Conclusion: (1)FABP2 gene polymorphism is exist in Tianjin Hangpopulation, and the codon-54 of mutant genotypic frequencies are in Hardy-Weinbergequilibrium. (2) FABP2 gene polymorphism is associated with type 2 DM. (3)FABP2polymorphism may have a certain contribution to dyslipidemia. (4)FABP2polymorphism may be associated with insulin resistance. (5)FABP2 genepolymorphism is associated with diabetic nephropathy, Individuals with FABP254Ala/Thr and Thr/Thr has a higher risk of diabetic nephropathy.更多还原