Determination of cell types and numbers during cardiac development in the neonatal and adult rat and mouse

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 293; no. 3; pp. H1883 - H1891
• Main Authors: Banerjee, Indroneal, Fuseler, John W, Price, Robert L, Borg, Thomas K, Baudino, Troy A
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.09.2007
• Subjects: Aging - pathology; Animals; Animals, Newborn; Cardiovascular disease; Cell Count; Cellular biology; Endothelium, Vascular - cytology; Female; Fetus - cytology; Fibroblasts - cytology; Flow Cytometry - methods; Heart; Heart - embryology; Heart - growth & development; Hydroxyproline - metabolism; Mice; Muscle, Smooth, Vascular - cytology; Myocardium - cytology; Myocardium - metabolism; Myocytes, Cardiac - cytology; Myocytes, Cardiac - metabolism; Pregnancy; Rats; Rodents; Studies
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.00514.2007

Cell and Developmental Biology and Anatomy, University of South Carolina School of Medicine, Columbia, South Carolina Submitted 30 April 2007 ; accepted in final form 28 June 2007 Cardiac fibroblasts, myocytes, endothelial cells, and vascular smooth muscle cells are the major cellular constituents of the heart. The aim of this study was to observe alterations in myocardial cell populations during early neonatal development in the adult animal and to observe any variations of the cardiac cell populations in different species, specifically, the rat and mouse. Whole hearts were isolated from either mice or rats during the neonatal and adult stages of development, and single cell suspensions were prepared via sequential collagenase digestion. Heterogeneous cell populations were immunolabeled for specific cell types and analyzed using fluorescence-activated cell sorting (FACS). In addition, the left ventricle, right ventricle, and septa were isolated, fixed, and sectioned for morphometric analyses. These same cardiac regions were also analyzed using FACS. We observed that the adult murine myocardium is composed of 56% myocytes, 27% fibroblasts, 7% endothelial cells, and 10% vascular smooth muscle cells. Moreover, our morphometric and FACS data demonstrated similar percentages in the three regions examined. During murine neonatal cardiac development, we observed a marked increase in numbers of cardiac fibroblasts and a resultant decrease in percentages of myocytes in late neonatal development ( day 15 ). Finally, FACS analyses of the rat heart during development displayed similar results in relation to increases in cardiac fibroblasts during development; however, cell populations in the rat differed markedly from those observed in the mouse. Taken together, these data enabled us to establish a homeostatic model for the myocardium that can be compared with genetic and cardiac disease models. cardiac fibroblast; myocyte; cardiac remodeling; flow cytometry Address for reprint requests and other correspondence: T. A. Baudino, Univ. of South Carolina School of Medicine, 6439 Garners Ferry Rd., Columbia, SC 29209 (e-mail: tbaudino{at}med.sc.edu )