Coxsackievirus infection in skeletal muscles of mice. An electron microscopic study. I. Cell- and nucleus alterations.

Abstract

Cell- and nucleus alterations of coxsackievirus A1 infected striated muscles of newborn mice are described: The first signs of an infection are always found in the nucleus, where the chromatin becomes condensed at the periphery. Swelling of the perinuclear space is followed by the development of vacuoles and channels formed by the nuclear membrane. This membrane coates also deep invaginations into the lobed nucleus. Electron-light areas of the nucleus contain granular and fibrillar inclusions. Only after the beginning of nuclear alteration, cytoplasmic degeneration is noted, starting with vacuolisation of the ER and going on with the disintegration of the contractile material followed by the formation of islets of organelles (vacuoles, mitochondria etc.) in large areas of completely disorganized filaments. The last stages are characterized by complete nuclear breakdown, loss of sarcolemm and immigration of phagocytes. These observations are compared with those made by other authors in genetic muscle dystrophies. The mechanisms of the cellular damage are discussed.