The quantitative expression of N-cadherin and Cx43 cultured for 3, 7 and 14 days.

<p>(<b>A, B, D, E</b>) N-Cadherin, PKP2 and PG significantly decreased at day 7 but significantly increased at day 14. (<b>A, C</b>) Cx43 increased a little at day 7 and then dramatically decreased at day 14. **<i>p</i><0.01; *<i>p</i><0.05.</p

Immunofluorescent staining and quantification of ID-related proteins of the EHTs cultured for 3, 7 and 14 days.

<p>(<b>A–D</b>) At day 3, the cell membranes were positively stained with N-cadherin, Cx43, PKP2 and PG. (<b>E–H</b>) At day 7, N-cadherin (<b>E</b>), PKP2 (<b>G</b>) and PG (<b>H</b>) staining were positive and mainly localized to the contact sites of adjacent cells (arrow). Whereas the Cx43 positive staining was distributed along the whole plasma membrane in a punctuate pattern (<b>F</b>). (<b>I–L</b>) At day 14, ID-related proteins concentrated at the polar ends (arrow) of cardiomyocytes. (<b>M</b>) The FI of N-Cadherin, PKP2 and PG decreased from day 3 to 7 but increased at day 14. Cx43 was expressed the opposite. **<i>p</i><0.01; *<i>p</i><0.05.</p

Immunofluorescent staining and quantification of ID-related proteins in primary cultured neonatal rat cardiomyocytes at different time point, adult and neonatal rat heart.

<p>(<b>A</b>) ID-related proteins were progressively changed their localization from the cells periphery to cell-cell contact sites. (<b>B</b>) ID-related proteins significantly increased at day 7 but slightly decreased (N-Cadherin, PKP2 and PG) or kept unchanged (Cx43) at day 14. **<i>p</i><0.01; *<i>p</i><0.05. (<b>C–D</b>) ID-related proteins accumulated in the contact sites of adjoining cells in neonatal and adult rat hearts. RC: rat cardiomyocytes; RH: rat heart.</p

Ultra-structures of the nascent ID in the EHTs cultured for 3 and 7 days.

<p>(<b>A</b>) Closely apposed cell membranes at day 3 with scarce plaque-like structure (black arrow), subplasmalemmal vesicles (dotted-line area) and fibril-like structure (arrowhead). (<b>B</b>) Adherens junctions (white arrow) and desmosomes (black arrow) dispersed among the ID at day 7. New intercellular junctions were forming (black-line area) and a single gap junction profile appeared (arrowhead). Note an adhesion region with a dense plaque of adherens junction (star) anchoring actin filaments and a desmosome (black arrow). Myo: myofibril; Z: Z-line; Nc: nucleus.</p