Treadmill exercise ameliorates dopaminergic neuronal loss through suppressing microglial activation in Parkinson's disease mice.
OBJECTIVE
Parkinson's disease is a debilitating neurodegenerative disorder characterized by the gradual loss of dopaminergic neurons. We investigated the effects of treadmill exercise on dopaminergic neuronal loss and microglial activation using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid (MPTP/P)-induced Parkinson's disease mice.


METHODS
Parkinson's disease was induced in mice by injection of MPTP/P. The mice in the exercise groups were put on a treadmill to run for 30min/day, five times per week for four weeks. Motor balance and coordination was measured using rota-rod test. Expressions of inducible nitric oxide synthase (iNOS) and phosphorylated extracellular signal-regulated kinase (p-ERK), phosphorylated NH(2)-terminal kinase (p-JNK), phosphorylated p-38 (p-p38), CD200, and CD200 receptor were determined by western blotting. Expressions of tyrosine hydroxylase (TH) and CD11b were evaluated by immunohistochemistry.


RESULTS
Parkinson's disease mice displayed poor motor balance and coordination with loss of nigrostriatal dopaminergic neurons. iNOS expression was enhanced via up-regulation of phosphorylated mitogen-activated protein kinases (p-MAPKs) signaling, such as p-ERK, p-JNK, and p-p-38 in the Parkinson's disease mice. Microglial activation was also observed in the Parkinson's disease mice, showing increased CD11b expression with suppressed CD200 and CD200 receptor expressions. Treadmill exercise prevented the loss of nigrostriatal dopaminergic neurons, and ameliorated the motor balance and coordination dysfunction in the Parkinson's disease mice. Treadmill exercise suppressed iNOS expression via down-regulation of MAPKs and also inhibited microglial activation in the Parkinson's disease mice.


CONCLUSIONS
Treadmill exercise prevented dopaminergic neuronal loss by inhibiting brain inflammation through suppression of microglial activation in the Parkinson's disease mice.
Department of Physical Therapy, Kyungnam University, Changwon 631-701, Republic of Korea.
Yun-Hee
YH
Sung
Shin-Chul
SC
Kim
Hoon-Pyo
HP
Hong
Chang-Youl
CY
Park
Mal-Soon
MS
Shin
Chang-Ju
CJ
Kim
Jin-Hee
JH
Seo
Dae-Young
DY
Kim
Dong-Je
DJ
Kim
Han-Jin
HJ
Cho
D000818:Animals; D001921:Brain / Q000378:metabolism / Q000503:physiopathology; D059290:Dopaminergic Neurons / Q000378:metabolism*; D015536:Down-Regulation; D007249:Inflammation / Q000503:physiopathology / Q000628:therapy*; D020935:MAP Kinase Signaling System / Q000502:physiology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D017628:Microglia / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics; D020734:Parkinsonian Disorders / Q000503:physiopathology / Q000628:therapy*; D010766:Phosphorylation; D010805:Physical Conditioning, Animal / Q000502:physiology*
D052247:Nitric Oxide Synthase Type II