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，

Key words: Outflow tract, Development, Transforming growth factor-β receptor, Immunohistochemistry, Mouse