Broadband multi-wavelength photobiomodulation improves pathological features in acute Parkinson’s disease mice

Parkinson’s disease (PD) has afflicted numerous patients and troubled countless families worldwide, but an effective therapeutic approach has not been discovered so far. Yet, emerging evidence suggested that photobiomodulation (PBM) can fundamentally delay and inhibit neuronal degeneration, and thus promisingly serve as a non-invasive alternative to conventional drug and surgical treatments. Nevertheless, the light wavelength and spectrum are crucial to PBM. To optimize the spectral formula of photomedicine and reveal photobiological effects, an acute PD model by injecting paraquat into mice abdomen was established in this study. Then, these mice were treated with the narrowband light-emitting diode (LED)-chip light peaked at 670 nm, the broadband phosphor-converted LED light peaked at 840 nm in 600−1000 nm region, and their combination. The results indicate that the PBM is safe, and the combined (narrow 670 + broad 840 nm) light exerted the most potent therapeutic effects. It significantly attenuated oxidative stress levels, enhanced axonal regeneration, protected dopaminergic neurons in the substantia nigra pars compacta (SNpc), preserved striatal neuronal integrity, and improved neuronal morphology and marker expression. Thereby, broadband wavelength through multitarget synergistic therapy helps to improving pathological features and facilitating neural function repair in acute PD mice. However, behavioral validation remains necessary in future studies and further richens the spectrum engineering to PBM.