Motoneuron degeneration after facial nerve avulsion is exacerbated in presymptomatic transgenic rats expressing human mutant Cu/Zn superoxide dismutase.
We investigated motoneuron degeneration after proximal nerve injury in presymptomatic transgenic (tg) rats expressing human mutant Cu/Zn superoxide dismutase (SOD1). The right facial nerves of presymptomatic tg rats expressing human H46R or G93A SOD1 and their non-tg littermates were avulsed, and facial nuclei were examined at 2 weeks postoperation. Nissl-stained cell counts revealed that facial motoneuron loss after avulsion was exacerbated in H46R- and G93A-tg rats compared with their non-tg littermates. The loss of motoneurons in G93A-tg rats after avulsion was significantly greater than that in H46R-tg rats. Intense cytoplasmic immunolabeling for SOD1 in injured motoneurons after avulsion was demonstrated in H46R- and G93A-tg rats but not in their littermates. Facial axotomy did not induce significant motoneuron loss nor enhance SOD1 immunoreactivity in these tg rats and non-tg littermates at 2 weeks postoperation, although both axotomy and avulsion elicited intense immunolabeling for activating transcription factor-3, phosphorylated c-Jun, and phosphorylated heat shock protein 27 in injured motoneurons of all these animals. The present data indicate the increased vulnerability of injured motoneurons after avulsion in the presymptomatic mutant SOD1-tg rats.
Ikeda
Ken
K
Department of Molecular Neuropathology, Tokyo Metropolitan Institute for Neuroscience, Tokyo, Japan.
Aoki
Masashi
M
Kawazoe
Yoko
Y
Sakamoto
Tsuyoshi
T
Hayashi
Yuichi
Y
Ishigaki
Aya
A
Nagai
Makiko
M
Kamii
Rieko
R
Kato
Shinsuke
S
Itoyama
Yasuto
Y
Watabe
Kazuhiko
K
D000818:Animals; D030801:Animals, Genetically Modified; D019771:Axotomy / Q000379:methods; D002452:Cell Count / Q000379:methods; D002470:Cell Survival / Q000502:physiology; D004195:Disease Models, Animal; D020220:Facial Nerve Injuries / Q000150:complications* / Q000378:metabolism*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D009046:Motor Neurons / Q000378:metabolism*; D009410:Nerve Degeneration / Q000209:etiology* / Q000378:metabolism*; D051381:Rats; D018709:Statistics, Nonparametric; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*
C109415:SOD1 G93A protein; D013482:Superoxide Dismutase