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目的探讨小鼠胚胎呼吸内胚层相关第二生心区(PSHF)发育与流出道远端形态发生的关系。方法用免疫蛋白印迹法检测抗胰岛因子-1(ISL-1)在80例胚龄10~14 d小鼠胚胎心脏标本的表达。另用抗ISL-1、抗α-平滑肌肌动蛋白(α-SMA)及抗心肌肌球蛋白重链(MHC)抗体,对36例胚龄11~13 d小鼠胚胎心连续石蜡切片进行免疫组织化学或免疫荧光染色。结果胚龄11~12 d是ISL-1蛋白在小鼠胚胎心脏表达的高峰时段。胚龄11 d,来自鳃弓或心包腔背侧壁等处PSHF的ISL-1阳性细胞延伸进入流出道远端管壁,流出道远端管壁则失去MHC表达,呈α-SMA阳性表达;来自PSHF的ISL-1阳性细胞则围绕呼吸内胚层呈对称性锥体结构分布,锥体顶端突入动脉囊腔呈ISL-1阳性突起。胚龄11.5 d,PSHF锥体顶端进入动脉囊头侧和尾侧管壁,形成流出道远端管壁上对称的ISL-1阳性柱结构;而动脉囊腔尚未分隔,流出道远端仍为单一管道。胚龄12 d,PSHF锥体突起失去ISL-1表达,呈较强的α-SMA表达。在PSHF锥体突起与流出道嵴融合前,两者之间出现主-肺动脉孔;两者融合后则形成α-SMA阳性的暂时性主-肺动脉隔,将动脉囊分隔成MHC阴性的心包内的主动脉和肺动脉。胚龄13 d,主-肺动脉隔逐渐消失,心包内主动脉和肺动脉分离。在MHC阴性的心包内大动脉管壁上出现了α-SMA阳性的平滑肌层,仍可见少量PSHF的ISL-1阳性细胞延伸进入心包内大动脉管壁。结论在小鼠胚胎发育11~13 d,PSHF将动脉囊分隔成心包内的主动脉和肺动脉,并参与心包内大动脉的侧面管壁和对侧面管壁的分化形成。
Objective To investigate the relationship between the development of mouse embryonic respiratory endoderm-related second-heart area (PSHF) and distal morphous of the outflow tract. Methods The expression of anti-Insulin-like factor-1 (ISL-1) in 80 embryos of 10-14 days old embryos was detected by Western blotting. Another 36 paraffin-embedded sections of embryos from 11 to 13 days old embryos were immunized with anti-ISL-1, anti-α-SMA and anti-myocardial MHC antibodies Histochemistry or immunofluorescence staining. Results The embryo age of 11-12 days was the peak period of ISL-1 protein expression in mouse embryonic heart. On the 11th day after embryo implantation, ISL-1 positive cells from PSHF at the branchial wall or dorsal wall of the pericardium extended into the distal wall of the outflow tract, while the MHC expression was lost at the distal wall of the outflow tract, showing α-SMA positive expression. ISL-1 positive cells from PSHF are distributed around symmetrical pyramidal structures of respiratory endoderm. The apical end protrudes into the arterial cyst with ISL-1 positive neurites. At embryonic age 11.5 d, the top of PSHF cone entered into the capsular and caudal wall of the artery, forming a symmetrical ISL-1 positive column structure on the distal wall of the outflow tract. However, the artery capsule was not separated and the distal end of the outflow tract was still Single pipe. On the 12th day after embryo implantation, the expression of ISL-1 was lost in PSHF pyramidal neurites, showing a strong expression of α-SMA. Before the PSHF pyramidal fusions merge with the outflow tract ridge, the main-pulmonary arterial foramina appear between the two; the fusion of the two forms a transient α-SMA positive-pulmonary artery septum, which separates the arterial sac into MHC-negative pericardial Of the aorta and pulmonary arteries. The age of embryo 13 days, the main - pulmonary artery gradually disappeared, pericardial aorta and pulmonary artery separation. Α-SMA positive smooth muscle layer appeared in the MHC-negative pericardium, but still a small amount of ISH-1 positive cells of PSHF extended into the pericardial wall of the aorta. CONCLUSIONS: During the embryonic development of mice, PSHF segregates the aortic and pulmonary arteries within the pericardium 11 to 13 days after mouse embryo development and participates in the formation of the lateral and distal lateral wall of the pericardium.