Expression of transforming growth factor-β receptors in the outflow tract of mouse embryonic heart / 解剖学报

ABSTRACT

Objective To investigate the spatiotemporal expression patterns of transforming growth factor-β(TGF-β) receptors type Ⅰ and type Ⅱ and their relationships with development of outflow tract(OFT) in mouse embryonic heart. Methods Serial sections of mouse embryos from embryonic day 9 (E9d) to embryonic day 14 (E14d) were stained using PAP immunohistochemical methods. Results Expressions of TGF-β receptors type Ⅰ (TGF-βRⅠ) and type II(TGF-βRⅡ) in the myocardial wall of OFT started at E10d, reached the reflection with splanchnic epithelium on the dorsal wall of the pericardial cavity at E11d. At E12d, expression intensity of TGF-βRⅠ and TGF-βRⅡ in myocardium increased to its highest level, and TGF-βRⅡ positive mesenchymal cells in OFT ridges could be detected. After E13d the staining intensity of TGF-βRⅠ and TGF-βRⅡ decreased rapidly,and at E14d,their expressions had fallen at the lowest.Conclusion The expressions of TGF-βRⅠ and TGF-βRⅡ in OFT are confined to the period of E10d to E14d, they may play important roles in regulating the myocardial cell proliferation, remodeling and septation of OFT, and promoting the differentiation from mesenchymal cells in the secondary heart field into smooth muscle cells in the distal end of OFT.