Mitochondrial alterations of skeletal muscle in a heat stress rat model
Hsu, Y.D.; Chen, S.S.; Lee, W.H.; Lin, S.Z.; Kao, M.C.; Tsao, W.L.
Proceedings of the National Science Council Republic of China. Part B Life Sciences 19(4): 233-239
1995
ISSN/ISBN: 0255-6596 PMID: 8742621 Document Number: 447108
The morphological and ultrastructural alterations of skeletal muscle in experimental rats with heat stress were investigated. Fifteen male Sprague-Dawley rats were exposed in a 42 degrees C constant temperature oven, resulting in a heat stress state; ten rats were used as controls. All treated rats had weakness of the 4 limbs associated with increased serum creatine kinase levels (p < 0.01). Soleus muscles were submitted to histological, histochemical, ultrastructural and quantitative-morphometric analysis. The group receiving heat stress showed many ragged-red fibers in Gomori trichrome stain and appeared hyper-reactive in succinate dehydrogenase and cytochrome C oxidase stains. The ultrastructure of ragged-red fibers showed increased mitochondrial aggregation as multiple small nests, which were particularly located in the subsarcolemmal space. The mitochondrial area was significantly increased in heat stress rats (p < 0.001). The consistently increased mitochondrial area and histochemical alterations of mitochondria are early pathological abnormalities in muscles with heat stress and indicate fundamental impairment of energy metabolism.