叶酸干预对神经管畸形鼠神经管发育的影响研究

The Influence of Folic Acid Intervention on the Development of Neural Tube Defect Rats' Neural Tubes

目的构建全反式维甲酸(all-trans retinoic acid,ATRA)诱导的神经管畸形鼠模型,探讨叶酸干预对神经管畸形(neural tube defects,NTDs)的预防作用,明确这一过程中Pax3基因表达的变化情况,为神经管畸形的早期防治提供可靠的理论依据。方法将18只性成熟健康雌性SD大鼠随机均分为3组:正常组、畸形组、叶酸干预组。其中,叶酸干预组于孕前2周喂食叶酸添加饲料(60μg·kg-1),直至终止妊娠;畸形组、叶酸干预组于妊娠第10天时给予ATRA(100mg·kg-1)一次性灌胃,正常组给予相同剂量橄榄油。妊娠第15天剖宫取胎,统计伴发畸形率并测定孕鼠血清叶酸、同型半胱氨酸(homocysteine,Hcy)含量及胎鼠Pax3基因表达量。结果 (1)畸形组畸形率(98.61%)高于叶酸干预组(35.09%)(P<0.01),正常组胎鼠未见畸形;(2)病理学观察发现正常组胎鼠发育正常,畸形组以显性脊柱裂为主,胎鼠背侧皮肤及皮下组织出现卵圆形缺损,神经管裸露或者膨出,叶酸干预组脊柱裂位置较畸形组低,缺损面积小,损害程度低;(3)叶酸干预组血清叶酸含量高于正常组与畸形组(P<0.05),畸形组Hcy含量高于正常组和叶酸干预组(P<0.05);(4)畸形组胎鼠Pax3基因表达量较正常组降低,叶酸干预组Pax3基因表达量较畸形组高(P<0.05)。结论叶酸干预可促进神经管正常发育,有效降低NTDs发生率。

Objective To establish the model of neural tube defect( NTDs) rats induced by all- trans retinoic acid( ATRA),to explore the preventive effect of folic acid intervention,and to confirm the expression of Pax3 gene in this process. Methods 18 sexually matured and healthy SD rats were divided into 3 groups randomly: normal control group,abnormal group,folic- acid intervention group. The rats in group 2 were fed with diets containing folic acid( 60μg·kg- 1) before two weeks of pregnancy until the end of gestation. Those in group 2 and 3 were one- time administered with ATRA( 100mg·kg- 1) in the 10 th day of gestation,while those in group 1 were administered with the same volume of olive oil as the control. After cesarean operation at the 15 th day of gestation,the incidence of malformation was calculated,the contents of folic acid and homocysteine( the reverse index of folic acid) in the pregnant rats' serum were detected,and the expression of Pax3 in fetal rats was tested. Results( 1) The incidence of malformation in abnormal model group( 98. 61%) was significantly higher than that in folic- acid intervention group( 35. 09%)( P < 0. 01),however,abnormal embryoswerenotfoundincontrolgroup.(2)Throughthepathologicalobservation,)wefoundthatfetalratsincontrolgroupdevelopednormally,whiledistinctspinalbifidawithoval defects at the back of skin and exposure or evagination of neural tube appeared in deratogenic group. The positions of spinal bifida with slighter damage were lower in folic acid intervention group,and the size of defective epidermis was smaller than abnormal group.( 3) The contents of folic acid in pregnant rats ' serum of folic- acid intervention group were significantly higher than those in both control and teratogenic model group( P < 0. 05). The content of Hcy in teratogenic model group was significantly higher than that in both control group and folic- acid intervention group( P < 0. 05).( 4) The results of gene detection showed that the expression of Pax3 in abnormal group's rats was significantly lower than that in the normal control group,in contrast,the level of Pax3 in folic- acid intervention group was significantly higher than that in teratogenic model group( P < 0. 05). Conclusion The folic intervention can promote the development of neural tube and decrease the the incidence of NTDs effectively.