RattenLiebe

Degenerative Myelopathy in Three Strains of Aging Rats
The syndrome is usually associated with aging since the paralysis has been seen only in rats more than 2
years old. Along with paralysis, severe atrophy of skeletal muscle in the posterior part of the body also has
been seen. The cause and pathogenesis are unknown. Some rats had tumors in the spinal cord or canal that
could have caused paralysis whilst others had large pituitary tumors.
However, in most rats, no specific cause could be found. All rats had grossly obvious atrophy of the loin and
hind legs. The fact that muscle atrophy is seen only in animals with some degree of paresis or paralysis tends
to support this. All rats with muscle atrophy had severe cord and nerve root lesions. Also, many animals with
advanced disease had obvious urinary incontinence, and some had enlarged urinary bladders at time of death.

Changes in the Nervous System and Musculature of Old Rats (http://vet.sagepub.com/content/8/4/320.full.pdf)
All animals were autopsied, and various organs were taken for histological examination. In addition to the
changes in the nervous system and musculature, the main pathological conditions observed were nephrosis,
adenoma of the pituitary gland, periarteritis nodosa, and, in the females, mammary adenomas
... rats showed posterior paralysis, whereas others, without exhibiting obvious signs of paralysis, had difficulty
in using their hind legs. The hind legs of some animals, when compared with those of young rats, were thin,
owing to an apparent reduction in the amount of muscular tissue.
Obvious macroscopic changes were not observed in the nervous system or skeletal musculature, except for
atrophy of the musculature of the hind legs in some rats. Histologically, there were lesions in the central and
peripheral nervous system as well as in the musculature.
Changes were obvious in the musculature of the hind legs of all rats examined, whereas the muscles of the
front legs showed no change in eight animals and only slight changes in the remaining 16 animals.
Quelle: vet.sagepub.com/content/13/5/321.full.pdf
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Changes in the Nervous System and Musculature of Old Rats
Published by: G. van Steenis and R. Kroes
This study was actuated by the observation of posterior paralysis and of apparent atrophy
of the musculature of the hind legs in rats over 2 years old.