Histological characteristics of stress-induced myopathy of the musculus longissimus dorsi in swine
Sośnicki, A.
Patologia Polska 36(3): 302-320
1985
ISSN/ISBN: 0031-3114 PMID: 3835514 Document Number: 254773
Histological (HE and Sudan III staining), histochemical (reaction for SDH, LDH, ATP-ase Mg++, AcP and glycogen content) and electron microscopic investigations of m. longissimus were carried out on 94 pigs. From 94 pigs 26 (27.66%) had characteristics histopathological features of exertional myopathy: proliferation of connective and fat tissue in endomysium, perivascular infiltrations, necrosis with phagocytosis of muscle fibers, giant fibers, decrease of SDH activity in .alpha.R fibers, lack of activity of SDH in type .alpha.W, diffusive decrease of SDH reaction in .beta.R fibers, strongly diffusive to total loss of ATP-ase Mg++ reaction in muscle fibers and in blood vessels, positive AcP reaction in giant fibers and in cells infiltrations, enlarged mitochondria with cristae atrophy and many positively contracted fibers. Those changes were more intensive in connective tissue than in the muscle fibers. The exertional myopathy nature of histopathological changes in giant fibers may confirm stress etiology of this fibers.