Influence of periodical mechanical stimulus on cardiac cell aggregates

In Physiology, numerous studies have provided evidence for electrical-mechanical interactions between cardiac cells in order to regulate the heartbeat. To investigate such interactions experimentally, a periodical mechanical stimulus has been applied to cardiac cell aggregates in a culture dish. The motion of the tip for the stimulus, tapping, replicated the intrinsic beat motion of the contraction and relaxation of the cell aggregates. Cardiac cell aggregates synchronize the beat with a periodical electrical stimulus in culture medium as the electrical stimulus is used for peacemaker. On the other hand, our mechanical tapping by a tungsten probe limited the area of the deformation on the aggregate surface. We will present the response of spontaneous aggregate beats to mechanical tapping, single or periodical at room temperature and in a standard culture condition. The results showed cardiac cell aggregates are not sensitive to mechanical stimulus relative to electrical stimulus, particularly in the culture condition. However, the partial synchronization and the spontaneous beat rate change under the stimulus in 24-48h indicates the biological modification may occur.