小鼠胚胎心脏各部分化发育成熟差异研究

Regional difference in cardiomyocyte differentiation and maturation of the embryonic mouse heart

目的探讨α-横纹肌肌动蛋白(α-SCA)、α-平滑肌肌动蛋白(α-SMA)和中间丝结蛋白与小鼠胚胎心脏分化发育成熟的关系。方法用免疫组化方法对胎龄9-19d小鼠胚胎心脏连续切片进行染色。结果胎龄9d,原始心室和流出道α-SCA、α-SMA表达较强,而结蛋白表达较弱。心房α-SCA、α-SMA的表达限于背侧壁和腹侧壁,静脉窦仅见少许α-SCA弱阳性细胞。心房和静脉窦则无结蛋白表达。胎龄10d,心房和心室膨出,心脏各部均表达较强的α-SCA、α-SMA和结蛋白。α-SCA、α-SMA和结蛋白的表达于胎龄12d达高峰。之后,α-SMA和结蛋白表达逐渐下降,但在右心室和流出道表达持续时间较长。结论α-SCA、α-SMA和结蛋白在小鼠胚胎心脏表达的时空特征表明小鼠胚胎心脏不同部位心肌分化发育成熟不同步。

Objective To investigate the relationship of α-sarcomeric actin（α-SCA）,α-smooth muscle actin（α-SMA）and intermediate filament protein desmin with the cardiomyocyte differentiation and maturation of the prenatal mouse hearts. Methods Serial sections of the embryo mouse hearts from embryonic day（ED）9 to ED19 were immunostained with antibodies against α-SCA,α-SMA and desmin. Results Primitive ventricle and outflow tract of heart at ED9 showed stronger expression of α-SCA and α-SMA,but lower desmin expression.In the atrium,the expression of α-SCA and α-SMA was restricted to the dorsal and ventral walls.In the sinus venosus,only few weakly stained α-SCA positive cells were detected.No desmin expression was found in the atria and sinus venosus.At ED10,atria and ventricles ballooned from the heart tube,and expression of α-SCA,α-SMA and desmin was strong in various parts of the heart.The expression of α-SCA,α-SMA and desmin peaked at ED12.After ED12,the expression of α-SMA and desmin gradually decreased in different parts of the heart,but in the right ventricle and outflow tract it was still strong. Conclusion The spatiotemporal expression patterns of α-SCA,α-SMA and desmin reveals regional differences in cardiomyocyte differentiation and maturation in various parts of the embryonic mouse heart.