Neuroprotective Effects of Filgrastim in Rotenone-Induced Parkinson's Disease in Rats: Insights into its Anti-Inflammatory, Neurotrophic, and Antiapoptotic Effects

All current treatments of Parkinson's disease (PD) focus on enhancing the dopaminergic effects and providing symptomatic relief; however, they cannot delay the disease progression. Filgrastim, a recombinant methionyl granulocyte colony-stimulating factor, demonstrated neuroprotection in many neurodegenerative and neurological diseases. This study aimed to assess the neuroprotective effects of filgrastim in rotenone-induced rat model of PD and investigate the potential underlying mechanisms of filgrastim actions. The effects of two doses of filgrastim (20 and 40 mu g/kg) on spontaneous locomotion, catalepsy, body weight, histology, and striatal dopamine (DA) content, as well as tyrosine hydroxylase (TH) and alpha-synuclein expression, were evaluated. Then, the effective dose was further tested for its potential anti-inflammatory, neurotrophic, and antiapoptotic effects. Filgrastim (40 mu g/kg) prevented rotenone-induced motor deficits, weight reduction, striatal DA depletion, and histological damage. Besides, it significantly inhibited rotenone-induced decrease in TH expression and increase in alpha-synuclein immunoreactivity in the midbrains and striata of the rats. These effects were associated with reduction of rotenone-induced neuroinflammation, apoptosis, and brain-derived neurotrophic factor depletion. Collectively, these results suggest that filgrastim might be a good candidate for management of PD.