Animal models utilized in research on muscular diseases in Japan.

A comparative study of human and animal muscular dystrophies revealed a number of differences in clinical symptoms and muscle pathology. In chicken muscular dystrophy (line 413), the white muscle was preferentially involved with striking vacuole formation in the sarcoplasm. Despite massive muscle fiber necrosis with phagocytosis which occurred in large groups in both hamsters (BIO 14.6) and mdx mouse dystrophies, the regenerating process compensated for the muscle fiber degeneration and resulted in no apparent clinical symptoms. Although the overall muscle pathology in dy mice (C57BL6J/dy+/dy+) including variation in fiber size, active fiber necrosis, interstitial fibrosis and progressive fatal course were very similar to those in human muscular dystrophy, dysmyelination at the anterior spinal roots in the mouse suggested the coexistence of neuropathic processes, which was probably involved in inducing muscle atrophy and weakness. A Japanese quail with slowly progressive muscle weakness was assumed to be a very important animal model for the adult onset type of human type II glycogenosis because there were very close morphological and biochemical similarities between the two species.