The effect of docosahexaenoic Acid on visual evoked potentials in a mouse model of Parkinson's disease: the role of cyclooxygenase-2 and nuclear factor kappa-B.

This study aimed to investigate the effect of docosahexaenoic acid (DHA) on visual evoked potentials (VEPs) in a mice model of Parkinson's disease (PD). Mice model was created by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and DHA was given by gavage. Cyclooxygenase-2 (COX-2), caspase-3 activities, nuclear factor kappa-B (NF-κB) and prostaglandin E2 (PGE2) levels were determined in substantia nigra (SN) and retina. Cyclooxygenase-2 intensities were also determined immunohistochemically. The tyrosine hydroxylase (TH) immunolabelling was significantly decreased in MPTP group compared to control. Docosahexaenoic acid decreased dopaminergic neuron death in MPTP + DHA group when compared to MPTP group. Mice treated with MPTP showed motor deficits as compared to control. Significant improvement was observed in MPTP + DHA group when compared to MPTP group. Treatment with MPTP significantly increased the activity of COX-2 and total COX in SN when compared to the control group. Docosahexaenoic acid caused a significant decrease in total COX and COX-2 activity in SN of mice given MPTP. Cyclooxygenase-2 showed strong immunostaining in MPTP group when compared to other groups in SN. Levels of PGE2 increased in MPTP group when compared to control in SN. Docosahexaenoic acid treatment in MPTP group reduced PGE2 in SN. Nuclear factor kappa-B levels were found to be decreased in SN of MPTP group. The mean latencies of P1, N1, P2, N2, P3, N3, P4, N4, and P5 VEP components were significantly prolonged in MPTP group when compared to control. In MPTP + DHA group, the mean latencies of all components except P5 returned to control values. Current data shows that DHA treatment improves prolonged VEPs latencies and locomotor activity.