中文摘要：

目的探讨肌特异性蛋白质在小鼠胚胎气道平滑肌的表达特点。方法用抗α-平滑肌肌动蛋白（α—SMA）、抗α-横纹肌肌动蛋白（α—SCA）和抗结蛋白（Desmin）单克隆抗体，对胎龄10～18d小鼠胚胎连续石蜡切片进行免疫组织化学显色。结果胎龄11～12d，前肠分隔为腹侧的气管和背侧的食管。胎龄12d，气管起始段后壁出现α-SMA阳性细胞，提示气管平滑肌开始发育，随着向气管下段延伸，α—SMA阳性逐渐减弱，肺静脉周围仅见极少量散在的α-SMA和α-SCA阳性细胞。胎龄13d，气管平滑肌理-SMA表达增强，并开始表达较弱的α-SCA和Desmin。胎龄14d，互为镜像的“c”形α-SMA阳性平滑肌表达出现在左、右支气管壁，α-SCA和Desmin的表达强度弱于α—SMA，此时肺静脉壁呈α—SMA强阳性表达。胎龄15d，α-SMA阳性平滑肌出现在细支气管壁。胎龄17～18d，平滑肌发育已延伸至终末细支气管，并显α-SMA阳性表达，而α-SCA和Desmin表达强度开始减弱。结论气道平滑肌发育始于胎龄12d气管上段，逐渐向下段延伸，胎龄18d，延伸至终末细支气管；Desmin的表达标志着平滑肌细胞骨架结构形成和气道平滑肌逐渐发育成熟，有助于气道平滑肌缓慢收缩功能的完善；气道平滑肌的发育早于肺静脉管壁平滑肌。

英文摘要：

Objective To investigate the developmental pattern of the airway smooth muscle in mice and the expression characteristics of different muscle-specific proteins. Methods Serial sections of mouse embryos from embryonic day 10 （ED10） to embryonic day 18 （ED18） were stained with monoclonal antibodies against α-SMA, α-SCA and Desmin. Results With the foregut gradually separating into trachea and esophagus, α-SMA positive cells were detected in the posterior wall of the initial segment of the trachea at ED12 and the expression intensity was tapered off towards the caudal segment. A few α-SMA and α-SCA positive cells were observed in the mesenchyme surrounding the developing pulmonary vein. At ED13, the expression intensity of α-SMA in the posterior wall of the trachea became stronger, while the very weaker expression of αSCA and Desmin was only initiated. At ED14, strong α-SMA expression showed C-shaped patterns in the wall of the left and right bronchi. However, staining intensity of α-SCA and Desmin at the same segment was weaker than that of α-SMA. In addition, the muscle cells of the pulmonary vein showed strong expression of α-SMA. At ED15, α-SMA positive cells were found in the wall of small bronchioles. Between ED17 and ED18, with progression towards the terminal bronehioles, expression intensity of α-SCA and Desmin became weaker in the airway smooth muscle while the expression of α-SMA became stronger. Conclusion The development of the airway smooth muscle begins from the upper segment of the trachea at ED12 and gradually extends distally. At ED18, airway smooth muscle cells have extended to the terminal bronchioles. The expression of Desmin marks the formation of smooth muscle cytoskeleton structures and implies the further maturation of the airway smooth muscle. Besides, it may help airway smooth muscle to improve peristaltic contraction function with the slow shortening speed. The appearance of the airway smooth muscle precedes the pulmonary vein vascular musculature.