In vitro determination and differentiation of mouse teratocarcinoma toward myocardiogenesis

Abstract Pluripotential mouse teratocarcinoma cells in embryoid bodies were explanted in vitro after which various modes of differentiation occurred. After about 5 days in culture, 1–4% of the piled-up colonies exhibited synchronized rhythmical contraction with a constant frequency ranging from 50 to 70 contractions/min, irrespective of the colony size. This phenomenon could be maintained for 25 days under our culture conditions. Ultrastructural studies of the rhythmically contracting colonies revealed determination and differentiation of embryonal carcinoma cells exclusively toward myocardiogenesis, and the developmental cellular stages were observed. Myocardial differentiation was characterized by the developmental stages of fibrillogenesis, accompanied by typical specialization of the myocardial-membrane complex. This myocardial differentiation bears a close similarity to the normal embryonic myocardiogenesis of 8- to 18-day mouse embryo heart.