Daily consumption of methylene blue reduces attentional deficits and dopamine reduction in a 6-OHDA model of Parkinson's disease - PubMed
Smith et al./PubMed/2018
Why It Matters
This paper caught my attention because methylene blue is dirt cheap and available now, unlike experimental drugs stuck in trials. The attention improvements are interesting since cognitive issues in Parkinson's are often harder to treat than motor symptoms. But here's the reality check: this is a rat study using a chemical toxin, not actual Parkinson's disease. The neuroprotection only worked when MB was given right as the brain injury happened — not a realistic scenario for humans who already have symptoms.
Key Findings
- Rats given 4 mg/kg methylene blue daily showed significantly better performance on attention tasks (five-choice serial reaction time test) compared to untreated Parkinson's model rats
- MB preserved some dopamine neurons in the substantia nigra when given alongside 6-OHDA toxin injection, suggesting neuroprotective effects
- The neuron preservation didn't translate to motor function improvements — rats still showed similar motor deficits regardless of MB treatment
- The study used 6-OHDA chemical lesions to mimic Parkinson's, which creates acute toxin damage rather than the progressive degeneration seen in actual human disease
- Timing matters: MB was given at the same time as the toxic injury, not after disease was established, making it unclear if it would help existing Parkinson's patients
Read the Paper↗PMID: 28694175