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目的探讨小鼠胚胎心流出道快速缩短及右心室形成机制。方法用抗α-横纹肌肌动蛋白(SCA)、抗肌球蛋白重链(MHC)抗体标记心肌,抗GATA-4抗体标记心肌及其前体细胞,抗α-平滑肌肌动蛋白(SMA)抗体标记早期心肌细胞,抗增殖细胞核抗原(PCNA)抗体显示增殖细胞,抗人/鼠活性Caspase-3(CAS-3)抗体检测凋亡早期细胞,对胚龄9d(E9)~E12(不同胚龄胚胎各取3~5只)小鼠胚胎心连续切片行免疫组织化学染色。结果E11时动脉囊及流出道远端心肌界退却至心包腔内,GATA-4、SCA、SMA染色示第二生心区前体细胞不断分化为心肌细胞添加在心动脉端使流出道延长。小鼠胚胎心流出道于E12缩短,缩短前及缩短过程中全长未检测到CAS-3阳性细胞。E10~12时右心室及流出道近段心肌不断增生形成小梁并侵入邻近的流出道嵴内,流出道近端嵴逐渐小梁状心肌化改建为右心室壁;E12时近段间充质性流出道嵴内出现散在的SCA、SMA阳性心肌细胞及与流出道心肌相延续的SCA、SMA弱阳性心肌细胞流,这些结果表明近段流出道心肌小梁化、流出道嵴小梁状肌化形成了右心室小梁部。结论小鼠胚胎流出道近段心室化致右心室小梁部形成及流出道快速缩短,心肌细胞凋亡及转分化对流出道快速缩短的作用甚微。
Objective To investigate the rapid shortening of cardiac exit and mouse right ventricular formation in mouse embryos. Methods Myocardium was labeled with anti-α-striated actin (SCA) and anti-myosin heavy chain (MHC) antibodies, anti-GATA-4 antibody labeled myocardium and its precursor cells, anti-α-smooth muscle actin (SMA) Early cardiomyocytes and anti-PCNA antibody were used to detect proliferating cells and anti-human / mouse active caspase-3 (CAS-3) antibody to detect apoptotic cells at early stage of embryonic day 9 (E9) ~ E12 Embryos each take 3 to 5) mouse embryos heart serial sections immunohistochemical staining. Results When E11, the distal myocardial territory of the arterial sac and the outflow tract retreated into the pericardial cavity. The GATA-4, SCA and SMA staining showed that the precursors of the second heart area continuously differentiated into cardiomyocytes and the outflow tract was prolonged when added to the heart. Mouse embryo cardiac outflow was shortened to E12, and CAS-3 positive cells were not detected in the whole length before and during shortening. E10 ~ 12, right ventricular and proximal myocardial outflow tract hyperplasia trabecular gradually invasive and invasive into the adjacent outflow ridges, the proximal crest of the outflow tract gradually trabecular-like myocardial into right ventricular wall; near E12 mesenchyme Scattered SCA, SMA positive cardiomyocytes and weak SCA and SMA positive cardiomyocytes were observed in the outflow ridges. These results indicate that the trabeculae of the proximal outflow tract and trabecular gluteus The formation of the right ventricular trabecular Ministry. Conclusion The formation and effusion of right trabeculae in the proximal part of mouse embryo outflow tract are rapidly shortened. The apoptosis and transdifferentiation of cardiac myocytes have little effect on the rapid shortening of the outflow tract.