n-3多不饱和脂肪酸通过调控Pax3-p53信号通路预防糖尿病孕鼠子代神经管畸形

Neural tube defects (NTD) are important reasons for infant death. Diabetic pregnancy can lead to the occurence of NTD, but folic acid supplementation cannot prevent all NTD induced by diabetic pregnancy. Our previous studies found that n-3 polyunsaturated fatty acids (n-3 PUFA) in human placenta are negatively associated with NTD risk in fetuses, and intake of n-3 PUFA during pregnancy can effectively prevent sodium valproate induced NTD in mice. However, whether n-3 PUFA can prevent diabetic pregnancy induced NTD is still unknown. In the present project, diabetic pregnant mice will be allocated to four groups: n-3 PUFA group, folic acid group, n-3 PUFA + folic acid group, and diabetic control group; another group of healthy pregnant mice will be included as healthy control group. We will explore the effect of n-3 PUFA on incidence of NTD in offspring of diabetic mice, and whether n-3 PUFA and folic acid can synergistically prevent diabetic pregnancy induced NTD. The potential mechanism will be explored by evaluating the effect of n-3 PUFA on apoptosis of neuroepithelial cell, mRNA and protein level as well as DNA methylation level of genes in Pax3-p53 apoptosis signal pathway in embryos. The present project can provide a new thought for preventing diabetic pregnancy induced NTD, and is quite meaningful for reducing NTD incidence in newborns.

神经管畸形（NTD）是导致婴儿死亡的重要原因。糖尿病妊娠可导致NTD的发生，但增补叶酸无法完全预防糖尿病妊娠诱发的NTD。申请人前期研究发现，人体胎盘中n-3多不饱和脂肪酸（n-3 PUFA）与NTD发病风险负相关，增补n-3 PUFA可预防丙戊酸钠诱发的小鼠NTD，但目前尚未有研究评价n-3 PUFA对糖尿病妊娠诱发的NTD的影响。本项目拟构建糖尿病孕小鼠模型，将其分为n-3 PUFA组、叶酸组、n-3 PUFA+叶酸组以及糖尿病对照组，并设健康对照组，探索n-3 PUFA对糖尿病孕鼠子代NTD发病率的影响，以及n-3 PUFA与叶酸对于预防该疾病是否存在协同作用；并通过研究n-3 PUFA对胚胎神经上皮细胞凋亡、Pax3-p53细胞凋亡信号通路中酶活性、基因表达及甲基化水平的影响阐明其预防机制。本项目可为预防糖尿病妊娠诱发的NTD提供新思路，对于降低新生儿NTD的发病率具有重要意义。

研究背景：糖尿病妊娠可导致子代NTD的发生，但增补叶酸（FA）无法完全预防糖尿病妊娠诱发的NTD。人体胎盘中n-3多不饱和脂肪酸（n-3 PUFA）与NTD发病风险负相关，增补n-3 PUFA可预防丙戊酸钠诱发的小鼠NTD，但目前尚未有研究评价n-3 PUFA对糖尿病妊娠诱发的NTD的影响。.研究内容：本项目主要研究孕期增补 n-3 PUFA 对糖尿病孕鼠子代 NTD 发病率、胚胎神经上皮细胞凋亡水平及 Pax3-p53 细胞凋亡信号通路的影响，并研究n-3 PUFA与FA在预防NTD中是否具有协同作用。本研究包括5组小鼠：健康对照组（HC）、糖尿病对照组（DMC）、糖尿病+n-3 PUFA组（DMn-3）、糖尿病+FA组（DMFA）和糖尿病+n-3 PUFA+FA组（DMFA+n-3）。.研究结果：DMC组NTD发病率为19.41%，孕期补充n-3 PUFA（DMn-3组）使子代NTD发病率显著降低至7.82%，该发病率与单纯补充FA组（DMFA组）的发病率（8.57%）相仿；DMFA+n-3组子代神经管畸形率仅为1.04%，显著低于DMn-3组和DMFA组，这表明n-3 PUFA和FA在预防糖尿病妊娠诱发的子代NTD中具有协同作用。DMC组子代神经上皮细胞出现严重的凋亡，凋亡率为88.19% ± 2.10%；与DMC组相比，DMn-3 和DMFA组子代神经上皮细胞凋亡率较低，分别为17.47 ± 3.01%和13.70 ± 1.66%；DMFA+n-3组子代神经上皮细胞的凋亡率（7.35 ± 1.48%）显著低于DMn-3 和DMFA组。与DMn-3 和DMFA组相比，DMFA+n-3组胚胎具有较低的P53 和Bax，较高的Pax3 and Bcl-2。n-3 PUFA与FA联用减轻了糖尿病引起的胚胎Pax3过度甲基化、Dnmt3b过表达和过高活性、一碳代谢紊乱以及过高同型半胱氨酸水平，并且这一效果优于单独补充n-3 PUFA或FA。.研究结论及科学意义：n-3 PUFA可通过调控Pax3-P53细胞凋亡信号通路预防糖尿病妊娠诱发的子代NTD，孕期n-3 PUFA与FA联用的预防效果优于单独补充FA。该发现为预防NTD提供了新思路，对于降低新生儿NTD的发病率具有重要意义。