Amelioration of L-DOPA-induced dyskinesia with vitamin D3 in Parkinsonian mice model

L-DOPA Induced Dyskinesia (LID) is associated with prolonged L-DOPA therapy. Vitamin-D receptor modulation improves motor-cognitive deficit in experimental LID Parkinsonism. Therefore, in this study, we investigated the mechanism underlying the anti-dyskinetic potential of Vitamin D3 (VD3). Dyskinesia was induced by chronic L-DOPA administration in 6-OHDA lesioned male C57BL6 mice. The experimental groups (Dyskinesia, Dyskinesia/VD3, and Dyskinesia/Amantadine) and controls were challenged with L-DOPA to determine the abnormal involuntary movements (AIMs) score during 14 days of VD3 (30 mg/kg) or Amantadine (40 mg/kg) treatment. Global behavioral Axial, Limb & Orolingual (ALO) AIMs were scored for 1 min at every 20 mins interval, over a duration of 100 mins on days 1,3,7,11 and 14 of treatment. Thereafter, brain samples were collected and processed for immunoblotting to assess striatal expression of tyrosine hydroxylase (TH), monoamine oxidase (MAO), cathecol-o-methyl transferase (COMT), dopamine decarboxylase (DDC), CD11b, BAX, P47phox, and IL-1{beta}. VD3 significantly attenuated ALO AIMs only on days 11 & 14, with maximal reduction of 32.7% compared with dyskinetic mice but had no effect on days 1, 3 & 7, while amantadine decreased AIMs all through days 1 to 14 with maximal reduction of 64.5%. TH and MAO-B expression were not significantly different across the groups. DDC was significantly suppressed in dyskinetic mice vs control (p<0.001) but remained unchanged in VD3 mice vs dyskinetic mice. COMT was upregulated in the dyskinetic group vs control (p<0.01) and attenuated in VD3 mice (p<0.05) compared to the dyskinetic group. Interestingly, VD3 inhibited significantly (p<0.01) oxidative stress (p47phox), apoptosis (BAX), inflammation (IL-1{beta}), and microglial activation (CD11b) in dyskinetic mice. Overall, we find that the anti-dyskinetic effects of VD3 is associated with modulation of striatal oxidative stress, microglial responses, inflammation, and apoptotic signaling. Impact statementThere are evidences showing that VD3 supplementation improves motor disorders, including Parkinsons disease. We hypothesized that VD3 could improve LID, an abnormal involuntary movement that results from prolonged L-DOPA therapy in the management of PD. We have demonstrated the novel anti-dyskinetic effect of VD3 and associated mechanistic factors in a mouse model of L-DOPA Induced Dyskinesia (LID), which identifies promising targets for dyskinesia therapy.