Degenerative Lesions of Spinal Roots and Peripheral Nerves in Aging Rats

Berg, Benjamin N.; Wolf, Abner; Simms, Henry S.

doi:10.1159/000211108

Cited by 67 publications

(27 citation statements)

References 4 publications

(7 reference statements)

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“…We have defined aged as the time point that coincides with the median survival age of the litter members. As described elsewhere (Berg et al, 1962;Van Steenis and Kroes, 1971;Burek et al, 1976;Mitsumori et al, 1981;Krinke, 1983;Johnson et al, 1995;Bergman and Ulfhake, 1998), rats show a progressive deterioration of motor behavior with advancing age, the symptoms usually starting during the third year of life and mainly affecting the hindlimbs (''posterior paralysis''). All aged rats used in this study disclosed clinical signs of behavioral sensory-motor dysfunction, defined according to a previously described staging protocol (Johnson et al, 1995).…”

Section: Experimental Animalsmentioning

confidence: 78%

“…However, peripheral nerves and dorsal roots of aged animals show abundant morphologic changes, including axonal dystrophy, demyelination, axonal degeneration, as well as loss of fibers (Berg et al, 1962;Gilmore, 1972;Burek et al, 1976;Sharma et al, 1980;Thomas et al, 1980;CotardBartley et al, 1981;Mitsumori et al, 1981;Krinke, 1983;Knox et al, 1989). Furthermore, a considerable and selective loss of cutaneous sensory nerve endings and receptor organs (Cauna, 1965;Fundin et al, 1997) have been observed with advancing age, with a more profound effect found on mechanoreceptive than nociceptive fibers (Fundin et al, 1997).…”

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confidence: 99%

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Effects of aging and axotomy on the expression of neurotrophin receptors in primary sensory neurons

1999

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Section: Experimental Animalsmentioning

confidence: 78%

mentioning

confidence: 99%

Effects of aging and axotomy on the expression of neurotrophin receptors in primary sensory neurons

1999

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“…No specific area of the cord was affected in rats from another study [13], and the dorsal column lesions appeared more pronounced than those in the rats reported here. The lesions in spinal cords from Sprague-Dawley rats were not confined to any particular region [3]. A demyelinating disease of two rats has been described [9].…”

Section: Discussionmentioning

confidence: 99%

Degenerative Myelopathy in Three Strains of Aging Rats

1976

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Absrracr. Spontaneous paresis and paralysis associated with degenerative spinal cord and spinal nerve root lesions occurred in three strains of rats used in studies of aging. Focal or segmental spinal cord lesions had mild to severe dernyelination, loss of nerve axons, and lipid-filled gitter cells. The lesions were limited to the white matter and were most severe in the lateral and ventral funiculi. The nerve roots had cholesterol clefts, focal hemorrhage, and demyelination. Atrophy of the skeletal muscle probably was secondary to the cord lesions. Vertebral lesions that involved the spinal canal and vascular blood flow were found, which may explain pathogenesis.Spontaneous posterior paralysis with associated spinal cord and spinal nerve root lesions occurs in several rat strains [3, 5, 131. 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 condition is progressive and eventually results in death. 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.Three different strains of rats were kept for aging studies at the Institute for Experimental Gerontology. Sporadic cases of paralysis occurred in two strains, but the incidence was very low. We have noticed that the third strain (F, hybrid of the other two strains) has a much higher incidence of posterior paresis and paralysis. Preliminary studies on these rats are presented and the pathologic features are compared to those in other reports [3, 5, 9, 131.

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“…Degenerative changes of the peripheral nervous system are common in these rats [3, 6, 7, 14, 361. These changes have been reported as "radiculoneuropathy" in Sprague-Dawley rats [3,41, and have been found in SPF Wistar strain [36], Charles River CD@ strain [8, 141 and BN/Bi, WAG/Rij and (WAG/BN)FI rats [6, 71. It has been shown that the lesions are prominent in the spinal nerve roots, especially from the lumbar roots to the cauda equina, but are not found in the nerve cells of the dorsal root ganglia and ventral horn of the spinal cord, the origin of these nerve fibers [3, 361.…”

mentioning

confidence: 94%

“…There is still no consensus on the primary site of the lesion, however, because nerve lesions in the peripheral nervous system usually include segmental demyelination with or without wallerian degeneration. Some investigators suggested that the segmental demyelination might be a primary change [3,141. In contrast, another investigator stated that the lesion combines wallerian degeneration and demyelination, with the former possibly being primary [36].…”

mentioning

confidence: 99%

An Ultrastructural Study of Spinal Nerve Roots and Dorsal Root Ganglia in Aging Rats with Spontaneous Radiculoneuropathy

Mitsumori¹,

Maita²,

Shirasu³

1981

Vet Pathol

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Abstract. The spinal nerve roots and dorsal ganglia of 104-to 135-week-old rats with spontaneous radiculoneuropathy were examined by light and electron microscopy.Demyelination was common in myelinated fibers of various diameters of both ventral and dorsal roots. The most striking alteration was wide distention of myelin sheaths, which extended throughout the entire internode. The spaces formed between separated lamellae frequently were invaded by macrophages. Subsequent vesicular degeneration of myelin seemed to be mediated by invading macrophages. These processes caused complete myelin destruction, but most axons showed no degenerative changes except for obvious reduction in diameter. Occasionally, there were clumping and partial degradation of neurofilaments and ruptured axolemma in the severely demyelinated axons. A few fibers also were undergoing walleriantype degeneration, perhaps secondary to the severe demyelinative changes. Remyelinating fibers in various phases of repair were coexistent with markedly demyelinated ones. Demyelinative changes described above also developed within some of these remyelinated internodes.There were no remarkable changes in neurons of the dorsal root ganglia, though accumulation of lipofuscin was common.Our findings suggest that the changes in the nerve roots are essentially a primary segmental demyelination in aging rats with radiculoneuropathy.It is well known that posterior paralysis occurs spontaneously in senile rats more than 2 years old. Degenerative changes of the peripheral nervous system are common in these rats [3, 6, 7, 14, 361. These changes have been reported as "radiculoneuropathy" in Sprague-Dawley rats [3, 41, and have been found in SPF Wistar strain [36], Charles River CD@ strain [8, 141 and BN/Bi, WAG/Rij and (WAG/BN)FI rats [6, 71. It has been shown that the lesions are prominent in the spinal nerve roots, especially from the lumbar roots to the cauda equina, but are not found in the nerve cells of the dorsal root ganglia and ventral horn of the spinal cord, the origin of these nerve fibers [3, 361. There is still no consensus on the primary site of the lesion, however, because nerve lesions in the peripheral nervous system usually include segmental demyelination with or without wallerian degeneration. Some investigators suggested that the segmental demyelination might be a primary change [3, 141. In contrast, another investigator stated that the lesion combines wallerian degeneration and demyelination, with the former possibly being primary [36].

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Degenerative Lesions of Spinal Roots and Peripheral Nerves in Aging Rats

Cited by 67 publications

References 4 publications

Effects of aging and axotomy on the expression of neurotrophin receptors in primary sensory neurons

Effects of aging and axotomy on the expression of neurotrophin receptors in primary sensory neurons

Degenerative Myelopathy in Three Strains of Aging Rats

An Ultrastructural Study of Spinal Nerve Roots and Dorsal Root Ganglia in Aging Rats with Spontaneous Radiculoneuropathy

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