Neuroprotective effect of nicotine against 3-nitropropionic acid (3-NP)-induced experimental Huntington's disease in rats.
Author: Tariq M, Khan HA, Elfaki I, Al Deeb S, Al Moutaery K.
Source:
Brain research bulletin, 67(1-2), 161-168.
Nicotinic acetylcholine receptors (nAChRs) are regarded as potential therapeutic
targets to control various neurodegenerative diseases. Owing to the relevance of
cholinergic neurotransmission in the pathogenesis of Huntington's disease (HD)
this investigation was aimed to study the effect of nicotine, a nAChR agonist, on
3-nitropropionic acid (3-NP)-induced neurodegeneration in female Wistar rats.
Systemic administration of 3-NP in rats serves as an important model of HD. The
animals received subcutaneous injections of nicotine (0, 0.25, 0.50 and 1.00
mg/kg) daily for 7 days. 3-NP (25 mg/kg, i.p.) was administered daily 30 min
after nicotine for the same duration. One additional group of rats served as
control (vehicle only). On day 8, the animals were observed for neurobehavioral
performance (motor activity, inclined plane test, grip strength test, paw test
and beam balance). Immediately after behavioral studies, the animals were
transcardially perfused with neutral buffered formalin (10%) and brains were
fixed for histological studies. Lesions in the striatal dopaminergic neurons were
assessed by immunohistochemical method using tyrosine hydroxylase (TH)
immunostaining. Treatment of rats with nicotine significantly and
dose-dependently attenuated 3-NP-induced behavioral deficits. Administration of
3-NP alone caused significant depletion of striatal dopamine (DA) and glutathione
(GSH), which was significantly and dose-dependently attenuated by nicotine.
Preservation of striatal dopaminergic neurons by nicotine was also confirmed by
immunohistochemical studies. These results clearly showed neuroprotective effect
of nicotine in experimental model of HD. The clinical relevance of these findings
in HD patients remains unclear and warrants further studies.