中文摘要：

目的探讨GATA4在生心区及前肠内胚层的时空表达与小鼠胚胎心动脉端发育的形态学关系。方法取胚龄7．5～13d小鼠胚胎各3个，连续石蜡切片，用抗GATA4、抗Nkx2．5、抗胰岛素增强子结合蛋白、抗a-平滑肌肌动蛋白和抗心肌肌球蛋白重链抗体，进行免疫组织化学或免疫荧光染色；Westernblotting检测GATA4与磷酸化组蛋白H3（pHH3）在胚龄11～14d小鼠胚胎心的表达。结果小鼠胚胎7．5d，GATA4和Nkx2．5同时表达于生心板，胚龄8．5～10d进一步表达于心包腔背侧壁第二生心区的脏壁中胚层，胚龄11～13d，两者的表达从流出道与心包腔背侧壁交界处降至主肺动脉根部。胚龄第11～13天，GATA4见于前肠内胚层。GATA4与pHH3的表达高峰见于胚龄11～13d，胚龄14d显著减少。结论小鼠胚胎发育早期，GATA4与Nkx2．5在生心区的表达模式相同，GATA4可能促进心肌细胞增生，前肠内胚层的GATA4可能参与第二生心区的发育。

英文摘要：

Objective To explore the relationship of the expression of transcriptional factor GATA4 in the heart- forming field and the foregut endoderm with the morphological development of the arterial pole of embryonic mouse heart. Methods Serial sections of mouse embryos on embryonic day（ ED）7.5 to ED13, three embryos from each embryonic day, were stained immunohistochemically or immunofluorescently with antibodies against GATA4, Nkx2. 5, insulin gene enhancer binding potein （ISL-1）, a-smooth muscle actin and myosin heavy chain. The expression of GATA4 and phosphorylated histone H3 （ pHH3 ） were measured with Western blotting in the embryonic mouse hearts from EDll to ED14. Results At ED7.5, positive cells for both transcription factors GATA4 and Nkx2. 5 were found in the cardiogenic plate simultaneously. From ED8.5 to ED10, further expression of GATA4 and Nkx2.5 were detected in the splanchnic mesoderm of the dorsal wall of the pericardial cavity that constituted the second heart field（ SHF）. From EDll to ED13, GATA4 and Nkx2. 5 expressions were found descending from the reflection of dorsal pericardial wall with the distal pole of outflow tract to the base of the ascending aorta and pulmonary trunk. GATA4 expression was also detected in the foregut endoderm of EDll to ED13 embryos. GATA4 and pHH3 expression in the embryonic mouse hearts reached the highest level between EDll and ED13. Conclusion Transcription factor GATA4 shows the same expression pattern as that of Nkx2.5 during the early development of the embryonic mouse heart. Higher expression of GATA4 during crucial stages of heart morphogenesis suggests that GATA4 may play an important role in the proliferation of myocardial cells. The GATA4 expression in the foregut endoderm may be involved in the development of the SHF.