ULTRASTRUCTURAL-STUDY OF CELL INJURY-INDUCED BY COXSACKIEVIRUS B3 IN PANCREATIC AND CARDIAC TISSUES

Balb/c weanling mice were intraperitoneally inoculated with a myocardi tic variant of coxsackievirus B3, with the aim of characterizing more thoroughly the features of virus-induced cell injury in pancreas and h eart, as well as to compare ultrastructural alterations with histologi cal and virological findings. During the first week postinfection (pi) , all animals developed acinar pancreatitis, followed by focal myocard itis. At electron microscopy, acinar cells showed patent distortion, i ncluding marked loss of organelles and zymogen granules, together with gross dilatation of rough endoplasmic reticulum. Cardiac cells presen ted severe cytoskeletal changes, as myofibrillar collapse with a hapha zard arrangement, concomitant with a decrease in myofibril number; bes ides, irregular pattern of nuclear chromatin and increased presence of swollen mitochondria were often observed. As the few initially detect ed lymphocytes tended to disappear in necrotic foci, there was an incr ease in fibroblast number concurrent with progressive scarring. Ultras tructural changes in both pancreas and heart correlated with local vir al replication, suggesting that cell damage is attributable to direct viral action.