Morphologische Untersuchungen an Hamstern des Stammes BIO 8262 mit erblicher Myopathie und Kardiomyopathie

Abstract

Introduction Morphological investigations of the myocardium and skeletal musculature of myopathic hamsters (strain BIO 8262) were performed. Material and Methods Myopathic hamsters 1 week to 35 weeks of age were sacrificed. Paraffin sections of the myocardium, musculus quadriceps femoris, musculus glutaeus maximus, diaphragm, the intercostal musculature and the tongue were studied with the light microscope. Results and Discussion Morphological changes in the myocardium appeared first in 6-week-old animals. The changes consisted of focal coagulation necroses which were resorbed by mononuclear cells. Furthermore, calcification of myocardial cells was evident. In most instances calcification occurred in multinucleated myocardial giant cells. In older animals the coagulation necrosis was regressive, giant cells disappeared, and calcific deposits were located in small scars of connective tissue. Changes in the skeletal musculature appeared earlier than in the myocardium. Already during the first week of life coagulation necroses were present. Necrotic material was resorbed by mononuclear cells similar as in the heart. Calcification was not as distinct as seen in the myocardium and was almost restricted to the diaphragm and tongue. In these organs beginning calcification was noticed as fine granular deposits lying parallel to the axis of the cells, presumably between the myofibrils. From this investigation it is concluded that destruction of myocardium takes place in two different ways: First, as coagulation necrosis, which is considered as a rapid cell decay. Second, as calcification, which induces formation of more slowly deteriorating myocardial giant cells. Since so-called Calcium antagonists' did prevent both forms of heart muscle decay ( Lossnitzer and Mohr, 1973 ) it may be concluded that the cellular deterioration is secondary to calcium overload as stated by Fleckenstein and coworkers (1971) .