Treadmill Exercise Attenuates l-DOPA-Induced Dyskinesia and Increases Striatal Levels of Glial Cell-Derived Neurotrophic Factor (GDNF) in Hemiparkinsonian Mice

Abstract

Exercise can act as a disease-modifying agent in Parkinson’s disease (PD), and we have previously demonstrated that voluntary exercise in running wheels during 2 weeks normalizes striatopallidal dopaminergic signaling and prevents the development of l-DOPA-induced dyskinesia (LID) in C57BL/6 mice. We now tested whether LID in Swiss albino mice could be attenuated by treadmill-controlled exercise alone or in combination with the reference antidyskinetic drug amantadine. The daily intraperitoneal (i.p.) treatment with three different doses of l-DOPA/benserazide (30/12.5, 50/25, or 70/35 mg/kg) during 3 weeks induced increasing levels of LID scores in hemiparkinsonian Swiss albino mice previously lesioned with a unilateral intrastriatal injection of 6-hydroxydopamine (6-OHDA, 10 μg). Then, we addressed the antidyskinetic effects of treadmill-controlled exercise by comparing LID, induced by l-DOPA/benserazide (50/25 mg/kg, i.p.) during 4 weeks, in sedentary and daily exercised mice. Exercise reduced LID and improved motor skills of dyskinetic mice, as indicated by decreased contralateral bias, increase in maximal load test, and latency to fall in rotarod. The antidyskinetic effect of amantadine (60 mg/kg, i.p.) was only observed in sedentary mice, indicating the absence of synergistic antidyskinetic effect of the combination of treadmill exercise plus amantadine. Finally, Western blot analysis unraveled an ability of exercise to increase the striatal immunocontent of glial cell-derived neurotrophic factor (GDNF), apart from normalizing striatal levels of tyrosine hydroxylase. These findings show that controlled treadmill exercise attenuates LID and provide the first indication that the antidyskinetic effects of treadmill exercise may involve increased striatal GDNF levels.