Cultured neonate rat myocytes as a model for the study of myocardial ischaemic necrosis

The preparation of cultures of neonate rat heart muscle cells is described. These cultures, when subjected to anoxia, show enzyme release that can be directly related to the uptake of a vital dye such trypan blue. Enzyme release is a valid method of estimating cell necrosis in this model. The survival of anoxic cultures is closely associated with glycolytic activity. Glycolysis rate falls and enzyme release increases as the medium glucose concentration is reduced. If glycolysis is inhibited by either 2-deoxyglucose or L-lactate, enzyme release under anoxic conditions is enhanced. Enzyme release correlates inversely with glycolytic activity and the intracellular ATP content of the cultures. Addition of ATP to anoxic cultures partially ameliorates the effect of the anoxia on enzyme release. Elevation of the calcium content of the culture medium exacerbates the damage caused to cardiac myocytes by anoxic insult. This effect can be obtunded by calcium-antagonist drugs such as verapamil or nifedipine and can be explained in terms of reduction in utilization of intracellular ATP by the anoxic monocytes. These observations indicate that cultured myocytes may represent a useful model of hypoxic injury against which novel pharmacological agents, that may reduce hypoxic or ischaemic injury in vivo, could be evaluated.