Muscular dystrophies are hereditary myopathies characterized by weakness and progressive muscular degeneration and consequently substitution for conjunctive and adipose tissue that can be appraised morphologically. The muscular dystrophy affects Golden retriever more often. It represents the most similar to the human disease in its clinical form--the reason why it was used as experimental model. Disease positive animals (n=6) from a Brazilian colony were used in this experiment. Death animals were submitted to necropsy. The elect muscles were immediately removed, collected in duplicate and microscopically appraised by histoquemistry and morphologic criteria. To accomplish the histopathological analyses, tissues fragments were processed by usual histopathologic criteria. The frozen fragments in liquid nitrogen were cut to 6 micrometers of thickness in the criostaty to 20 degrees Celsius under zero and put in slides in other to be stained by means of adenosine triphosphatase (ATPase) reaction with acid and alkaline pre-incubation and non-specific esterase reaction. Dystrophic animals presented clinical signs such as weakness and muscular atrophy and serum creatine quinase (CK) high levels. Histopathological alterations were identified in every muscle for eosin haematoxylin (HE) and modified Gomori trichrome (GT) staining. Variations in fiber diameter, necrosis, fibrosis, inflammation and regeneration were diagnosed in every muscle in different degrees of intensity. Hyalinization and mineralization were also observed in most of the examined muscles. The qualitative analysis of the degree of existent lesion is in agreement with the extension of miofibers damages indicated variable degrees in the different ages. The degree of attack of the muscles seems to show a positive correlation with animal age. Seemingly, it seems that there is no preferential involvement of the affected muscles.

Supported by Fundação de Amparo à Pesquisa do Estado de São Paulo-FAPESP, Brazil.

References

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