Post mortem, ultrastructural cardiac muscle changes and anthracycline toxicity.

Anthracycline induced cardiomyopathy is commonly evaluated using the ultrastructural investigation of myocardial tissue. This is based to a large degree on subjectively evaluated, studies of post-mortem material which report various fin structural changes of cardiac tissue as being characteristic of this cardiomyopathy. We have studied the morphological variations of normal myocardial tissue in rats following perfusion fixation and immersion fixation of tissue obtained at death as well as at time points up to 6 hours after death, to examine the fine structural changes associated with immersion fixation and post mortal artefacts. Mitochondria profile area (reflecting mitochondrial swelling--a factor constantly reported as typical of anthracycline damage) increased significantly (p less than 0,01) if there was any delay between cell death and fixation. Many other fine structural changes were noted. We conclude that studies of this nature should ideally be carried out in experimental systems using perfusion fixation. Fixation procedures must always be defined in detail. If post mortem material must be used adequate information on the duration of the autolytic period must be given.