COMPARATIVE HISTOMORPHOLOGY BETWEEN ISOPROTERENOL-INDUCED EARLY LESIONS AND POSTMORTEM ARTIFACTS IN THE RAT-HEART

Isoproterenol-induced early myocardial lesions were compared histomorp hologically to commonly observed postmortem artifacts in the rat heart s which were collected up with 40 min after death. Isoproterenol-induc ed early lesions were characterized by multifocal myocardial eosinophi lia restricted to the inner one third of the left ventricle and septum . These very early lesions were similar to the artifacts which were al so characterized by myocardial eosinophilia and increased with time af ter death. The dilation of intercellular spaces which was also an arti fact occurred at 40 min. Contraction bands, fragmentation of fibers an d inflammatory cellular infiltration noted only in the isoproterenol-i nduced lesions were the differentiating criteria from artifacts. The p ostmortem artifacts were not observed in the hearts fixed immediately after death.