中文摘要：

目的利用Cx43基因剔除（KO）小鼠模型,观察TGFβ2在心脏流出道隔的表达,探讨Cx43基因剔除小鼠心脏流出道隔心肌化异常与TGFβ2的关系;采用胚心脏体外培养技术,研究外源性TGFβ2是否促进流出道隔心肌化过程.方法选用胚E12.5～E15.5 d的Cx43基因剔除纯合型（Cx43-/-）、杂合型（Cx43＋/-）及野生型（Cx43＋/＋）C57/BL6小鼠作为研究对象,采用PCR方法鉴定基因型,免疫组织化学法测定TGFβ2;选用野生型E12.5进行胚心脏体外培养至E15.5,同时加用TGβ2不同剂量干预处理,免疫组织化学法测定肌节肌动蛋白α-SCA的表达.结果 Cx43 KO小鼠胚期心脏近端流出道隔心肌细胞明显减少,尤其以E13.5和E14.5的Cx43-/-小鼠为著.与Cx43＋/＋小鼠对照,Cx43-/-小鼠心脏近端流出道隔TGFβ2的表达明显降低,以E14.5较为显著;E14.5的Cx43＋/-小鼠表达也有降低.然而TGFβ2不同剂量干预组均没有见到明显的促进离体心脏心肌化的作用.结论 Cx43 KO小鼠心脏近端流出道隔存在明显的心肌化延迟.TGFβ2表达减少可能参与了Cx43-/-小鼠心肌化异常的发病机制.体外应用TGFβ2可能难以模拟在体的时空表达模式,或者心肌化的进行需要精确的TGFβ2的剂量和严格的培养条件.

英文摘要：

Objective To investigate the expression of TGFβ2 in proximal OFT septum in connexin （Cx） 43 knockout （KO） mice and illustrate its relationship with myocardialization and reveal whether exogenous TGFβ2 could promote myocardialization in vitro. Methods Objects were C57/BL6 mice of E12.5 to E15. 5 by the mating of 2 month old Cx43 heterozygous mice, which included Cx43 homozygotes （ Cx43 - / - ）, heterozygotes （ Cx43 ＋ / - ） and wild-types （ Cx43 ＋ / ＋ ） genotyped by PCR method, u-sareomeric actin（u-SCA） and TGFβ2 were detected by immunohistochemistry. TGFβ2 with 3 different dosages was used to be the intervent added to the heart culture system in which the wild-type hearts of E12.5 were cultured till E15. 5 before detecting the expression of α-SCA by immunohistochemistry. Results The expression of α-SCA in the proximal OFT septum was delayed obviously in Cx43 - / - predominantly at E13.5 and E14.5. As compared with the Cx43 ＋ / ＋ , the expression of TGFβ2 in proximal OFT septum decreased obviously in Cx43 -/- mice predominantly at E14.5, and less obviously in Cx43 ＋ / - mice. None of the intervention groups showed the obvious promoted myocardialization. Conclusions Cx43 KO mice exhibited delayed myocardialization, and the decreased TGFβ2 may involve in the abnormal myocardialization of Cx43 KO mice. Application of TGFβ2 in vitro could not exactly mimic the in vivo expression pattern of TGFβ2, or the process of myocardialization may require precise dosage of TGFβ2 and stringency of cultured system.