Neuroprotective effect of thymoquinone, the nigella sativa bioactive compound, in 6-hydroxydopamine-induced hemi-parkinsonian rat model

ABSTRACT

Parkinson disease [PD] is the most common movement disorder with progressive degeneration of midbrain dopaminergic neurons for which current treatments afford symptomatic relief with no-prevention of disease progression. Due to the neuroprotective property of the Nigella sativa bioactive compound thymoquinone [TQ], this study was undertaken to evaluate whether TQ could improve behavioral and cellular abnormalities and markers of oxidative stress in an experimental model of early PD in rat. Unilateral intrastriatal 6-hydroxydopamine [6-OHDA]-lesioned rats were daily pretreated p.o. with TQ at doses of 5 and/or 10 mg/Kg three times at an interval of 24 h. After 1 week, apomorphine caused contralateral rotations, a reduction in the number of neurons on the left side of the substantia nigra pars compacta [SNC] was observed, malondialdehyde [MDA] and nitrite level in midbrain homogenate increased and activity of superoxide dismutase [SOD] reduced in the 6-OHDA lesion group. TQ pretreatment significantly improved turning behavior, prevented loss of SNC neurons,and lowered level of MDA. These results suggest that TQ could afford neuroprotection against 6-OHDA neurotoxicity that is partly due to the attenuation of lipid peroxidation and this may provide benefits, along with other therapies, in neurodegenerative disorders including PD