Effects Of Two Drugs On The Brain Development Induced By Alcohol Exposure In Mouse

BackgroundDrinking are becoming common with the improvement of social economy and living standard.Alcohol is a central nervous system depressants and chronic or excessive drinking could lead to alcohol poisoning.Alcohol can cause damages of multiple systems and organ,such as the digestive system,cardiovascular system,nervous system,even cancer,et al[1-4].In the process of development,the central nervous system is very sensitive to alcohol exposure[5,6].Pregnancy exposured by high dose of alcohol could induce fetal alcohol syndrome(FAS).That is after birth the fetus presenting growth retardation,abnormal facies,and the central nervous system(CNS)dysfunction etc.[7-9].Researches have shown that a single alcohol injection could damage neural stem cells of hippocampus and purkinje cells and bergman glial cells of cerebellum in mices,that induced unrepaired cells loss[10,11].Alcohol could damage limbic system especially for hippocampus causing memory impairment in adolescence[12-14].In magnetic resonance imaging research showed that the volume of hippocampal decreased in adolescent alcohol abuse and alcohol dependence that inducing learning and memory impaired[15-19].Neurogenesis continue and participate in learning,memory and other cognitive function in the hippocampus.Furthermore,high dose of alcohol exposed to adolescent rats could damage the structure of hippocampus and induce abnormal praxiology function[20],even impaire the neurogenesis until adulthood[21].Radial glial cells(RGCs)are recognised as morphologically,biochemically and functionally distinct from other neural cell types and are the first appeared glial cells with stem cell function in the embryonic period.They display an apical-basal polarity possessing a periventricular cell body which is early neural epithelial layer of the neural tube and an elongated process extending from a ventricular attachment to an end-foot anchored to the opposing pial surface.RGCs are recognized as neural stem cells and play a very vital role in the development of CNS[22],The development and differentiation of RGCs is governed by a series of factors[23].In addition,RGCs as stem cells are also present in two regional proliferation in the adult CNS: subventricular zone(SVZ)and subgranular zone(SGZ)of dentate gyrus(DG)[24].Radial glial cells(RGCs)act as neural progenitor and precursor cells in the development of lamellar structure(hippocampus,cortex and cerebellum),which can not only serve as neural precursor cells to generate neurons and glial cells,but also display a radial glial scaffold by its long trunk[23,25,26].RGCs in the development of DG can be divided into primary RGCs and secondary RGCs.Similar to the RGCs in the neocortex,primary RGCs appear in the prenatal phase of DG development and span the entire length from the fimbria to the pial surface of the DG.Young neurons and precursor cells migrate along their fibers from the neuroepithelium to the DG anlage.Secondary RGCs are derived from nonradial precursor cells in the early postnatal DG,which in turn are the most important precursor cells at later stages of DG morphogenesis.The secondary RGCs in the mouse fully develop their radial glial scaffold.Then,they initiate the final transformation into astrocytes and translocate through the GCL to populate the ML.Only a few secondary RGCs remain into adulthood,and these cells comprise the stem cells responsible for adult neurogenesis in th DG[23][15].The bergman glial cell(BG)derives directly from cerebellar RGCs and its morphology is similar to hippocampus and cortex of RGCs,exhibiting long radial fibers extending toward the pial surface[11,26].BG provide trails to guide the migration of different cell types,essential for the correct patterning of cortical foliation and layering in the context of cerebellar corticogenesis and regulate the directional elongation of axons and dendrites[26].Recent studies have shown that BG affect and conduct the dendrite development of Purkinje cells,which finally influence the formation of dendritic spine and synapse and promote the normal conduction of signals[27].Studies have shown that maintaining the unique morphology of BG and its scaffolds contributes to the survival of Purkinje cells[28].We use the following two drugs,including oxytocin(OT)and resveratrol(RSV),observing OT and RSV are influence on the development of adolescent brain and neonatal cerebellum after alcohol exposure and in order to improve the developing brain damage after alcohol exposure and provide a new clinical treatment for alcohol use disorders.OT is composed of nine amino acids of pituitary neuropeptides,mainly synthesized by the supraoptic nucleus of hippocampusand paraventricular nuclei.The secretion of OT is controlled by the hypothalamic-pituitary-gonadal axis adjustment.In adolescence,the development of hypothalamic-pituitary-sexual is becoming maturation,secretion of OT is to a new level.Initially it has always been to adopt the clinical application of oxytocin in order to treat prolonged uterine contraction,also known as " oxytocin ".Recent studies have shown that oxytocin can also promote cell proliferation and hippocampal neurogenesis[29].Besides,it plays an important role in mammal maternal behavior,mate bonding,social recognition,stress,anxiety,and many other social behaviors[30,31].Now few study about oxytocin on the adolescent brain development in mice induced by alcohol exposure injuries.Therefore,mice following exposure to alcohol during adolescence,we used OT be treated and with a view to improving the developing brain injury caused by alcohol exposure.Natural stilbene RSV,mainly exist in the red grape and in certain medicinal plants[32,33].Our laboratory found that RSV could protect the RGCs in the hippocampal dentate gyrus and improve the neurogenesis of neonatal mice from alcohol exposure,which can reduce the damage of alcohol exposure.However,it's not clear whether RSV could have effect that related pathways and mechanisms on the cerebellum.Based on our previous studies.Therefore,in our research,we use RSV protect the development of cerebellum in the neonatal mice from exposure to alcohol,with a view to reducing damage caused by alcohol exposure on the development of cerebellum at neonatal mouse.Methods and ResultsThe first part:Effects of OT on the development of the brain of adolescent mice induced by alcohol exposure1.Immunohistochemistry results showed that bromodeoxyuridine(BrdU)positive cells increased in the hippocampus dentate gyrus,indicating that OT could improve the newborn neurons after alcohol exposure in dentate gyrus of adolescent mice.2.Immunohistochemistry results showed that parvalbumin(PV)positive interneurons increased in the hippocampal dentate gyrus,indicating that OT could improve the inhibitory PV positive interneurons after alcohol exposure in dentate gyrus of adolescent mice.3.Immunohistochemistry results showed that both Sry-related HMG box2(Sox2)and glial fibrillary acidic protein(GFAP)positive cells by commom markers increased in the hippocampal dentate gyrus,indicating that OT probably could improve the RGCs after alcohol exposure in dentate gyrus of adolescent mice.The second part: Effect of RSV on the cerebellar development of neonatal mouse induced by alcohol exposure1.Immunohistochemistry results showed that calbindin D-28K(CBD-28K/CB)positive cells increased in the cerebellum,indicating that RSV could improve the Purkinje cells after alcohol exposure in the cerebellum of neonatal mouse.2.Immunohistochemistry results showed that brain lipid-binding protein(BLBP)and GFAP positive cells increased in the cerebellum,indicating that RSV could improve the Bergman glial cells after alcohol exposure in the cerebellum of neonatal mouse.3.Immunohistochemistry and western blot(WB)results showed that ionized calcium-binding adapter molecule 1(Iba1)positive cells and expression of nuclear factor-?-gene binding(NF-?B)decreased in the cerebellum,indicating that RSV could reduce the microglia cells after alcohol exposure in the cerebellum of neonatal mouse.ConclusionsThese results indicated that OT and RSV could protect the brain development caused by alcohol exposure,which probably dues to the protection of radial glial cells and the reduction of cell damage and loss.