Effect of an antioxidant-enriched diet on deposition of oxidative damage products and amyloid in brain tissue of old dogs

Veterinary practitioners frequently
encounter dogs suffering from a
clinical syndrome of age-related
cognitive dysfunction. This dementia
syndrome in dogs appears to be
largely analogous to the human
form of senile dementia of the
Alzheimer type (SDAT). The
histopathological changes in the
canine brain related to Alzheimer’s
disease (AD) consist of moderate ßamyloid
deposition, accumulation of
end-products of oxidative damage
such as lipofuscin and 4-
hydroxynonenal, cerebral vascular
changes, dilation of the ventricles
and neuronal cytoskeleton changes.
In the present study the effect of an
antioxidant-enriched diet on the
deposition of amyloid and
accumulation of lipofuscin was
investigated. Four groups of dogs
were used in this study. Group one
consisted of old demented dogs that
received an antioxidant-enriched
diet, group two contained old
demented dogs, group three old nondemented
dogs, and group four
consisted of young dogs. Dementia
scores of these dogs were determined
in an earlier study by an owner
questionnaire. The brains were
histologically examined for Aßamyloid
and lipofuscin depositions.
The results of the present study
showed that the antioxidantenriched
diet did not significantly
lower the dementia score, the
amount of amyloid in total brain
tissue and the amount of lipofuscin
in the parietal gyrus. However, the
diet had a significant positive effect
on the amount of lipofuscin in the
frontal gyrus.
The conclusion of the presentstudy
is that the antioxidant-enriched diet
decreases the amount of lipofuscin
in particular in the frontal part ofthe brain what is the major cognitive
site.