Spontaneous Formiation Cell Clusters in Cultured Cardiac Myocytes

Spontaneous formation of cell clusters was experimentally studied for a cardiac cell culture system. A primary cell culture prepared from a newborn rat was cultivated and continuously observed using microscopy. It was observed that the cells start to form small clusters, and then form a network of clusters, which was generated on a timescale of one week. It was found that addition of an agent that suppresses the beating motion of cardiac cells results in inhibition of the cluster formation. From these observations, it is concluded that the mechanical tension owing to the beating motion of cardiac cells drives the formation of clusters. Furthermore, we show that substrates affect the orientations of cells and the cluster formation, through experiments using collagen gel substrates. On the basis of experimental results, we propose a hypothesis concerning the mechanism of cluster formation