小鼠胚胎细胞视黄酸结合蛋白1阳性神经嵴细胞的时空分布与功能

Distribution and function of cellular retinoic acid binding protein 1 positive neural crest cells of mouse embryo

目的探讨小鼠胚胎心神经嵴细胞的形成、分布模式及其在心血管系统发育过程中的作用。方法选用抗细胞视黄酸结合蛋白1(CRABP1)、抗α-平滑肌肌动蛋白(α-SMA)、抗心肌肌球蛋白重链(MHC)、抗胰岛因子1(Isl-1)抗体,对45只胚龄8～12d小鼠胚胎连续切片进行免疫组织化学染色。结果胚龄8d,CRABP1在神经褶的外胚层未见阳性表达。胚龄8.5～9d,在心管与鳃弓水平,神经褶开始出现CRABP1阳性细胞,且有部分细胞从神经褶背侧分离进入邻近间充质。胚龄10d,神经管两侧间充质内的CRABP1阳性细胞迁移至鳃弓、弓动脉壁内皮周围以及流出道心胶质内。胚龄11～12d,弓动脉内皮周围、流出道心内膜垫内CRABP1表达明显下降,但弓动脉管壁α-SMA阳性平滑肌细胞数量增加。主肺动脉隔及其分隔形成的升主动脉和肺动脉干管壁内均可见Isl-1阳性细胞,但未见CRABP1表达。结论小鼠胚胎CRABP1阳性神经嵴细胞形成的时间窗限定在胚龄8.5～9d。胚龄10d后,CRABP1阳性神经嵴细胞经过迁移,参与弓动脉中膜平滑肌和流出道心内膜垫的形成。CRABP1不能用于标记迁移后的神经嵴细胞。

Objective To investigate the formation and the distribution pattern of cardiac neural crest and its function during the development of cardiovascular system of mouse embryo. Methods Serial sections of forty-five mouse embryos during embryonic day （ ED ） 8 to ED 12 were stained immunohistochemically with antibodies against cellular retinoic acid binding protein 1 （ CRABP1 ） , α-smooth muscle actin （α-SMA） , myosin heavy chain （MHC） and islet-1 （ Isl-1 ）. Results At ED8, CRABP1 had not been expressed in the ectoderm of neural fold. During ED8.5 to ED9, at the level of cardiac tube and branchial arch, immunohistochemical positive reactive cells for CRABP1 were observed in neural fold and a part of them delaminated from neural fold entered into the neighbor mesechyme. At EDIO, CRABP1 positive cells in the bilateral mesenchyme of the neural tube migrated into branchial arch, exterior of aortic arch endothelium and the cardiac jelly of the outflow tract. From EDll to ED12, CRABP1 expression in immunohistochemical reactive positive cells was down-regulated in the mesenchyme surrounding the aortic arch endothelium and in the endocardial cushion. While α- SMA immunohistochemical positive staining intensity in the smooth muscle cells of aortic arch wall was increased. Isl-1 positive ceils were shown in the aortic-pulmonary septum and the walls of ascending aorta and pulmonary trunk septated by the septum, where CRABP1 was negative staining. Conclusion The time window of CRABP1 positive neural crest formation is from ED8.5 to ED9 in mouse embryo. After EDIO, CRABP1 positive cells migrate and contribute to the formation of the tunica media smooth muscle of the aortic arch and endocardial cushion of the outflow tract. CRABP1 could not be used to mark the neural crest cells after migration.