MTHFR、HCY与BDNF在大鼠胚胎神经管畸形发生中的作用

摘要

Objective To study the role of folate homocysteine metabolism key enzyme methylenet-etrahydrofolate reductase(MTHFR),homocysteine(HCY)and brain-derived neurotrophic factor (BDNF)in the rat neural tube defects pathogenesised. Methods A total of 30 adult female SD rats were randomly divided into normal group,all-transretinoic acid(ATRA)group and folic acid treatment group,with 10 rats in each group. HCY concentration in plasma of pregnant rats on E15.5d of gestation was determined by ELASA. The expression of MTHFR and BDNF in E15.5d embryonic neural tube tissue was examed by using immunohistochemistry analysis. The embryonic neural tube tissue cell apoptosis was checked by TUNEL staining. Results Compared with the normal group,HCY concentration increased in deformity of pregnant rats plasma(P<0.05). Mean optical density (MOD)value of immunohistochemical staining for MTHFR,BDNF factor in embryonic neural tube defect tissue decreased(P<0.05). TUNEL staining showed that the cell apoptosis increased in embryonic neural tube defect tissue(P<0.05). Adding folic acid treatment group in plasma HCY concentration of pregnant rats had no significant change(P>0.05). MOD of MTHFR and BDNF in embryonic neural tube tissue decreased (P<0.05). TUNEL staining showed no obvious changes of embryonic nerve tube nerve cell apoptosis(P>0.05). Compared with the neural tube defect group, in folic acid treatment group, Hcy plasma concentration of pregnant rats decreased (P<0.05),MOD of MTHFR,BDNF increased in the embryonic neural tube tissue and the apoptosis of neural cells reduced(P<0.05). Conclusion The decreased expression of MTHFR in neural tube defects rats induced HCY accumulation in the tissue of neural tube tissue,decreased the expression of BDNF and increased apoptosis of embryonic neural cells, which led to defects in the closure of neural tube tissue. Folic acid can inhibit the process,so as to effectively prevent the most of pathogenesis in neural tube defects.%目的 研究叶酸-同型半胱氨酸代谢途径中关键酶亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase, MTHFR)、同型半胱氨酸(homocysteine,HCY)与脑源性神经营养因子(brain derived neurotrophic factor,BDNF)在大鼠神经管畸形发生中的作用.方法 将30只成年雌性SD大鼠随机分为正常对照组(正常组)、神经管畸形组(畸形组)、叶酸干预组(叶酸组),每组各10只.于孕鼠妊娠第15.5天时,采用酶联免疫吸附法(ELISA)测定孕鼠血浆HCY浓度;取大鼠胚胎,免疫组织化学染色分析胚胎神经管组织MTHFR、BDNF表达量、TUNEL染色(过氧化物酶标记测定法)分析胚胎神经管组织细胞凋亡率.结果 与正常组相比,畸形组孕鼠血浆HCY浓度升高(P<0.05),胚胎神经管组织中MTHFR、BDNF因子的免疫组织化学染色平均光密度(MOD)值下降(P<0.05),TUNEL染色显示胚胎神经管组织中细胞凋亡率升高(P<0.05),叶酸组孕鼠血浆HCY浓度无明显变化(P>0.05),胚胎神经管组织中MTHFR、BDNF的免疫组化染色MOD值下降(P<0.05),TUNEL染色显示胚胎神经管组织神经细胞凋亡率无明显变化(P>0.05).与畸形组比,叶酸组孕鼠血浆Hcy浓度降低(P<0.05),胚胎神经管组织中MTHFR、BDNF因子的MOD值升高(P<0.05),TUNEL染色显示神经细胞凋亡率降低(P<0.05).结论 胚胎神经管组织发育中MTHFR表达降低致HCY蓄积,引起BDNF表达下调,细胞凋亡增加,从而导致神经管关闭受阻;叶酸补充后较好地逆转这一过程,从而预防大部分神经管畸形的发生.