Muscular atrophies in stranded cetaceans in Canary islands between 1996-2008

Abstract

Gross and histopathologic evaluatíon of skeletal muscle was performed in 148 stranded cetaceans of 21 dífferent species, undergoing post-mortem examination in Canary !slands. Animals were evaluated for grossly evident muscle lesions, and muscle samples were fixed in formalin, processed routinely, and stained with haematoxylin and eosin, PhosphotungsHc Acid Haemotoxylin, periodic acid-Schiff for glucogen, ond Von Kosso for calcium. In addition, immunohistochemical examination was performed using primary monoclonal (fast and antí­slow myosin heavy chain) and polyclonal antibodies (myog!obin and fíbrinogen). Generalized or focal/multifocal muscular atrophy was the second rnost common muscular fínding and it was detected in 42 animals (28,4%). Morphological diagnosis of muscular atrophy was made based on: decrease myofiber diameter, increased fiber síze variation, morphological myofiber alterations, endomisial fibrosis, fíber type involved and alterations in fíber type distríbution. The combínation of hístopathologícal findings and overa!! data concerníng the cause of death was useful in arder to establish an aetiological diagnosis of muscular atrophy in these animals. Cachexia/malnutrition and senilíty were the first common cause of muscular atrophy in stranded cetaceans (40,5%, respectively), followed by denervatíon atrophy (16,7%) and disuse atrophy (2,4%). Morphologícal and lesiona! pattern of each atrophy group will be discussed.