Ventricularization of the proximal cardiac outflow tract contributes to trabeculated right ventricle in mouse embryo
10.3969/j.issn.0529-1356.2014.05.020
- VernacularTitle:小鼠胚胎心流出道近段心室化形成右心室小梁部
- Author:
Hairong LI
;
Yanping YANG
;
Jingjing WANG
;
Ximei CAO
;
Huixia LIU
;
Huilin CUI
;
Tao ZHANG
;
Ya JING
- Publication Type:Journal Article
- Keywords:
Embryo;
Cardiac outflow tract;
GATA-4;
α-Sarcomeric actin;
α-Smooth muscle actin;
Proliferating cell nuclear antigen;
Immunohistochemistry;
Mouse
- From:
Acta Anatomica Sinica
2014;(5):698-703
- CountryChina
- Language:Chinese
-
Abstract:
Objective To explore the mechanism underlying the rapid shortening of outflow tract and the formation of the right ventricle of the embryonic mouse heart .Methods Serial sections of embryonic mouse hearts from embryonic day 9 (E9) to E12(3 to 5 embryos for each stage)were stained with antibodies against α-sarcomeric actin (SCA), α-smooth muscle actin (SMA), GATA-4, myosin heavy chain (MHC), proliferating cell nuclear antigen (PCNA) or active caspase-3 (CAS-3).Results At E11, the aortic sac and the distal border of cardiac outflow tract had regressed towards the ventricle into the pericardial cavity , while GATA-4、SCA and SMA staining showed that precursors from the second heart field were differentiating into cardiomyocytes adding to the arterial pole of the heart to lengthen the outflow tract .The length of outflow tract rapidly shortened at E12.Before and during its shortening , no CAS-3 positive cell was detected in the entire outflow tract.During E10-12, the cardiomyocytes in the right ventricle and proximal outflow tract wall proliferated inward to form trabeculae, with some trabeculae extending into the ridges .Proximal extremities of the outflow tract ridges were gradually myocardialized remodeling into the trabeullar right ventricle wall .At E12, scattered SCA and SMA staining cells and SCA and SMA weak positive mesenchymal cell clusters , which were continuous with the outflow tract myocardium were detected in the mesenchymal proximal outflow tract ridges .These results suggested that the proximal outflow tract was remodeled into the right ventricle by trabecularization , during which mesenchymal ridges were trabecularlly myocardialized . Conclusion Ventricularization of the proximal outflow tract contributes to the trabecular right ventricle and resultes in the vapid shortening of outflow tract in the mouse embryonic heart .Cardiomyocyte appoptosis and transdifferentiation are found to play a more limited contribution during this process .
