| Research Abstract |
Age-related changes in the canine substantia nigra were examined by using immunostaining for tyrosine hydroxylase (TH). Histopathologically, several age-related changes, including lipofuscin deposition, polyglucosan bodies, amorphous basophilic inclusions and esoinophilic crystal inclusions were found in aged dogs. Immunohistochemically, TH-positive neurons were well preserved in dogs examined, however, the ratio of TH-positive neurons to GFAP-positive glial cells tended to show slight decrease in aged dogs. By ssDNA immunostaining for apoptotic cells, there were no significant results. The number of ubiquitin- and NF-positive swallen neurites was increased markedly in aged dogs. Ubiquitin-immunostaining revealed a small number of basophilic and esoinophilic inclusions, although these inclusions were negative for NF. By αSN immunostaining, no neurons were immunoreactive and no basophilic or eoinophilc intracytoplasmic inclusions were revealed. These results indicate that in the substantia nigra of aged dogs the dopaminergic neurons are well preserved, but intracytoplasmic inclusions and ubiquitin-positive degenerative neurites are commonly found. All these results have been already published in J. Vet. Med. Sci.
In the cerebral cortex and hippocampus, the number of senile plaques tended to increase according to aging. However, there was no significant relationship between the number of senile plaques and SS-DNA positive neurons, indicating beta-amyloid deposits did not induce direct neuronal apoptosis. These results have still not been published.
By the support of this grant, several neurological cases had been collected, and already reported in scientific journals as case reports.
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