Remote photobiomodulation targeted at the abdomen or legs provides effective neuroprotection against parkinsonian MPTP insult.
Level 5 - mechanism / opinion, no new human data
Preclinical animal model study (CEBM Level 5)
PubMed 36949610 · doi:10.1111/ejn.15973
What was done
Researchers evaluated whether remote photobiomodulation (PBM) directed at the abdomen or legs could protect against MPTP-induced neurotoxicity compared to transcranial PBM. In a pilot study, abdominal PBM (670 nm, 50 mW/cm², 6 min/day) was tested in a single MPTP-treated non-human primate (n = 1) relative to untreated MPTP controls. Validation studies tested abdominal, leg, and transcranial PBM in MPTP-injected mice (n = 10 per group), assessing midbrain dopaminergic cell survival and striatal axonal terminals.
What was found
In the non-human primate pilot (n = 1), abdominal PBM was associated with fewer clinical signs and greater midbrain dopaminergic cell survival compared to untreated controls (no exact numerical values reported). In MPTP-injected mice (n = 10 per group), PBM to the abdomen or legs significantly rescued midbrain dopaminergic cells (~80%, p < .0001 for both) and striatal axonal terminals, achieving neuroprotection comparable to or greater than transcranial PBM.
Why it matters
Targeting light therapy to peripheral tissues circumvents skull and scalp attenuation that limits transcranial photobiomodulation in humans. These findings indicate that peripheral tissue irradiation can confer central neuroprotection in preclinical Parkinson's disease models.
Limits
The non-human primate experiment was a single-animal pilot (n = 1). The findings rely entirely on acute toxin-induced (MPTP) animal models, which may not capture the complex, progressive pathophysiology of human Parkinson's disease. Exact absolute cell counts and the systemic mechanisms linking peripheral light application to central neuroprotection were not detailed in the abstract.
Cited by
- supports Shining red light on the abdomen reduces Parkinson's disease symptoms and cell loss in primate models of the disease.