Endurance exercise training protects against the upregulation of nitric oxide in the striatum of MPTP/probenecid mouse model of Parkinson's disease.

OBJECTIVES

Parkinson's disease (PD) is a neurodegenerative disorder, caused by the gradual loss of cells in substantia nigra. Nitric oxide (NO) plays an important role in a variety of signal transduction pathways that are crucial for maintaining the physiologic functions of nervous system. The aims of this study are: 1) To investigate the expression of the inducible form of NO (iNOS), and compare it to neuronal nitric oxide (nNOS) in the brain of a chronic mouse model of PD and 2) To study the effect of endurance exercise training on the expression of these markers.

METHOD

Mouse models of PD were obtained using 10 doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (25 mg/kg) and probenecid (250 mg/kg) over 5 weeks. Forty C57BL /6 albino mice were randomly divided into four groups: sedentary control (SC, N = 10), exercise control (EC, N = 10), sedentary PD (SPD, N = 10), exercise PD (EPD, N = 10). At the end of training program, nNOS and iNOS were evaluated in the striatum in all animal groups using immunohistochemistry.

RESULTS

nNOS showed significant increases in striatum (ST) of SPD mice compared to SC mice (P > 0.03). There was also decreased expression of nNOS in EC group compared to SC mice, but this decrease was not significant (P > 0.8). Exercise training significantly decreased the level of nNOS in the EPD compared to SPD, (P > 0.04). Although, iNOS expression followed almost the same trend as nNOS, but exercise training did not significantly decrease the expression of iNOS in both EC and EPD groups, P > 0.2 and 0.3 respectively.

DISCUSSION

The data from this study suggests that 4 weeks of treadmill exercise has a positive impact on the expression of nNOS and iNOS in the striatum of a PD model. This might clear in part the pathogenicity of the diseases and the positive impact of training on PD.