TITLE:
Neuroprotective Effects of Caffeine on a Maternally Separated Parkinsonian Rat Model
AUTHORS:
Thabisile Mpofana, Willie M. U. Daniels, Musa V. Mabandla
KEYWORDS:
Maternal Separation; 6-Hydroxydopamine; Parkinson’s Disease; Behavioural Tests; Caffeine
JOURNAL NAME:
Journal of Behavioral and Brain Science,
Vol.4 No.2,
February
18,
2014
ABSTRACT:
Early-life
stress has been shown to disrupt the programming of the hypothalamic-pituitary-adrenal
(HPA) axis which may have severe consequences in the development of
neurological disorders later on in life. Prolonged early-life stressful events
produce an exaggerated stress hormone response in the adult offspring. Chronic
stress and elevated corticosterone levels have been found to exaggerate
functional deficits and accelerate loss of dopamine producing neurons in a rat
model of Parkinson’s disease. We investigated the neuroprotective effects of
caffeine on 6-OHDA lesioned rats that were exposed to maternal separation
stress. We examined behaviour of animals before and after the infusion of
6-OHDA using the step and cylinder tests. We also measured dopamine
concentration in the striatum, mitochondrial membrane potential in the striatum
and the total antioxidant capacity in blood plasma. Maternally separated rats displayed an impaired ability to initiate
movement in the step test and a decreased percentage impaired limb use in the
cylinder test. In the rats that received caffeine these motor deficits were
ameliorated. Maternal separation exaggerated the lesion caused by 6-OHDA
injection. However, the neuroprotective effects of caffeine were evident in
both the stressed and non-stressed rats as shown by the higher dopamine
concentration and total antioxidant capacity on caffeine treated rats.
Maternally separated rats had higher mitochondrial membrane permeability when
compared to the caffeine treated rats. We therefore conclude that caffeine
ameliorated the neurodegeneration associated with 6-OHDA injection in maternally
separated animals.