神经营养因子、凋亡相关因子和轴突导向因子在大鼠神经管畸形发育中的表达

Expression of Neurotrophic Factors,Apoptosis Related Factors and Axon Guidance Factors in Rat Neural Tube Defects

目的探讨神经营养因子(NT-3,CNTF,IGF-1,PDGF)、凋亡相关因子(Caspase-3,Bcl-x)l、轴突导向因子(Netrin)的mRNA在大鼠神经管畸形发育中的表达变化.方法选取孕鼠随机分为正常组(不作任何处理)、对照组(按50 mg/kg橄榄油于E10 d时一次性胃饲孕鼠)和(按50 mg/kg溶于橄榄油的维甲酸于E10 d时一次性胃饲孕鼠).正常组、对照组和实验组又各自分为E15d、E16 d、E17 d、E18 d、E19 d、E20 d组,每组5只胎鼠,用于RT-PCR实验.结果 (1)实验组的胎鼠中66%发生了死胎、脊髓脊柱裂、无尾畸形、下肢不发育等;(2)神经营养因子(NT-3,CNTF,IGF-1,PDGF)、凋亡相关因子(Caspase-3,Bcl-x)l、轴突导向因子(Netrin)在E15 d～E20 d正常及畸形大鼠神经管发育过程中,均有表达.其中,IGF-1在E16d与正常组比较表现为表达减少的趋势;实验组内比较IGF-1表达有先增加后减少再增加的趋势.CNTF在E17d时与正常组比较表达有减少.以上变化均具有统计学意义(P<0.05).凋亡因子(Caspase-3,Bcl-x)l和导向因子(Netrin)均无统计学意义.结论神经营养因子(NT-3,CNTF,IGF-1,PDGF)、凋亡相关因子(Caspase-3,Bcl-x)l、轴突导向因子(Netrin)在E15 d～E20 d正常及畸形大鼠神经管发育过程中有重要作用.IGF-1、CNTF的mRNA变化均较正常组有不同程度减低,可能是维甲酸通过干扰此三类神经营养因子等大分子物质在发育过程中的形成和分布,在某种程度上改变了大鼠神经胚发育的进程和方式,以此也就干扰了神经元的正常的分化增殖发育过程.

Objective To observe the changes in the expression of the neurotrophic factors（NT-3,CNTF,IGF-1 and PDGF）,apoptosis related factors（Caspase-3 and Bcl-xl）and axon guidance factor（Netrin） in rat neural tube defects.Methods The pregnancy rats were divided into normal（Nothing was done for the peragnancy rats in normal group）,control（olive was intragastic administrated by 50mg per kilogram in E10d peragnancy day one time in contral group）and experimental groups（All-trans Retinoic Acid（ATRA）was dissolved in the olive,ATRA was intragastric administrated by 50mg per kilogram in E10d peragnancy day one time）randomly.Each group was subdivide into E15d,E16d,E17d,E18d,E19d and E20d groups,and five anmals in each group were used for Rever Transcription Poly-merase Chain Reaction（RT-PCR） experiment.Results 1.In experiment group,dead embryo,cranical meningocele,no tail deformities,and nondevelpoment of the hind limbs occurred in about 66% embryo.2.The expression of neurotrophic factors（NT-3,CNTF,IGF-1 and PDGF）,apoptosis related factors（Caspase-3 and Bcl-xl）and axon guidance factor（Netrin）was found in normal and neural tube defects rats on E15d～E20d.The expression of IGF-1 had a decreasing tendency in neural tube defects rats on E16d,and had a fluctuation in experiment groups.The expression of CNTF was downregulated in experiment groups on E17d,compared with control group.There were statistically significant differences in the above changes.The expression of Caspase-3,Bcl-xl,and Netrin had no statistically significant changes.Conclusions 1.The neurotrophic factors（NT-3,CNTF,IGF-1 and PDGF）,apoptosis related factors（Caspase-3 and Bcl-xl） and axon guidance factor（Netrin）play important roles in the development of neural tubes of normal and defected rats on E15d～E20d.2.The expression of IGF-1 and CNTF mRNA in experimental group is downregulated in experiment groups,compared with the normal control group,suggesting that RA may interfere the forming and distributing of these factors in the development of neural tube,then change the process and mode of the development of the rat neural embryo,thus interfere the normal differentiation and proliferation of nerve cells and lastly induce the nerve tube defect.