Effects Of Maternal Folic Acid During Pregnancy On Neurodevelopment And Learning/Memory Ability In Rat Offspring

Objective Maternal folic acid(FA)supplementation during periconceptional period decreases neural tube defects incidence and benefits cognitive performances in offspring,but there is no consensus about whether FA should be supplementated continuously throughout pregnancy.Through one-carbon metabolism,folate supports nucleic acid synthesis and DNA methylation that important for development and function of central nervous system.The present study aimed to investigate the effects of maternal FA intake during pregnancy on offspring’s neurodevelopment and learning/memory ability,discover the necessetity of prolonged matermal FA supplementation throughout pregnancy,and provide novel insights into the deeper mechanism study with DNA methylation involved.Methods Female SD rats were devided into FA-deficient(FA-D),FA-normal(FA-N),FA-supplementated short-perid(FA-S),and FA-supplementated long-perid(FA-L)groups.Blood samples in dams,brain tissue and hippocampus–derived neural stem cells(NSCs)cltures in neonatal offspring were collected;another part of offspring were raised for neurobehavioral tests.(1)Serum folate: measured by automated chemiluminescence system;(2)neurobehavioral development: assessed by bibrissa placing,air righting,auditory startle and gait reflex tests;(3)spatial learning/memory ability: assessed by Morris water maze test;(4)brain tissue: ultrastructural changes,aboundance of neuron and proliferative NSCs,protein expressions of brain-derived neurotrophic factor(BDNF)and synaptophysin were assessed by transmission eletron microscopy,immunofluorescence,and western blots,respectively;(5)NSCs cultures: cell viability,proliferation,and neuron differentiation were measured by Alamar Blue,Brd U incorporation,and immunocytochemistry;(6)differential methylated genes were identified by Me DIP-chip,pathways implicated in neurodevelopment and learning/memory ability were identified by KEGG pathway analysis.Results(1)Maternal FA supplementation promotes neurobehavioral reflex maturation,and exerts long-term improvements in spatial learning/memory ability and hippocampal ultrastructural in offspring.FA-L group showed improved performaces of bibrissa placing,gait reflex,and learning/memory ability than did FA-S group.(2)Maternal FA supplementation increased neuron and proliferative NSCs in hippocampus;increased cell viability,proliferation,and neuron differentiation in NSCs clutures;increased neuron and BDNF,SYP protein expression in cortex.FA-L group showed increased neuron and proliferative NSCs in hippocampus;increased cell viability and proliferation in NSCs clutures than did FA-S group.(3)Signaling pathways regulating pluripotency of stem cells,autophagy,tight junction,calcium signaling pathway,m TOR signaling pathway,Notch signaling pathway,Neurotrophin signaling pathway,protein processing in endoplasmic reticulum,c GMP-PKG signaling pathway,gap junction,Rap1 signaling pathway,and endocytosis were methylated differentially in FA-D/FA-N.Signaling pathways regulating pluripotency of stem cells,autophagy,tight junction,calcium signaling pathway,MAPK signaling pathway,TGF-β signaling pathway,axon guidance,c GMP-PKG signaling pathway,gap junction,Erb B signaling pathway,Glutamatergic synapse,and Neuroactive ligand-receptor interaction were methylated differentially in FA-L/FA-N.Conclusion Maternal FA supplementation during pregnancy,especially if prolonged throughout pregnancy,improves neurobehavioral development and learning/memory ability in rat offspring,its may attribute to the stimulation of hippocampal neurogenesis and cortical synaptogenesis.The study indicated its potential mechanisms regulated by DNA methylation.The study provide scientific basis for rational FA supplementation in women,and provide novel insights into further mechanism study.