Low-moderate dose whole-brain γ-ray irradiation modulates the expressions of GFAP and ICAM-1 in the MPTP-induced Parkinson’s disease mouse model

Abstract

The anti-inflammatory efficacy of radiation therapy (RT) with single fractions below 1.0 Gy has been demonstrated in Alzheimer’s disease mouse models. As neuroinflammation is also a major pathological feature of Parkinson’s disease (PD), RT may also be effective in PD treatment. Therefore, this study aimed to investigate the anti-inflammatory effect of low-moderate dose RT (LMDRT, 0.6 Gy/single dose, for 5 days) exposure in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 30 mg/kg, i.p., for 5 consecutive days)-induced PD mouse model. Importantly, LMDRT reduced the levels of glial fibrillary acidic protein (GFAP) and intercellular adhesion molecule-1 (ICAM-1, CD54) in the striatum region, which increased following MPTP administration. LMDRT also modulated inflammatory gene expression patterns in the substantia nigra region of the MPTP-treated mice. However, LMDRT had no direct effects on the severe loss of dopaminergic neurons and impaired motor behavior in the rotarod test. These results indicate that LMDRT has anti-inflammatory effects by modulating neuroinflammatory factors, including GFAP and ICAM-1, but showed no behavioral improvements or neuroprotection in the MPTP-induced mouse model of PD.