Highlights
- In a mouse model of inflammatory pain, Class 3B laser photobiomodulation (PBM) reduced pain sensitivity in a dose-dependent
- The strongest and most consistent effects were seen at mid-range doses (rather than the lowest or highest).
- Repeated daily sessions helped maintain pain reduction over time.
- Swelling (edema) did not meaningfully change, suggesting PBM may primarily affect pain signaling, not inflammation-related swelling in this model.
- These results help inform how researchers think about optimizing PBM dosing for pain-related applications.
Why this matters
With PBM, “more” isn’t always better. Like many biological interventions, the body can respond best within a sweet spot — a dose that’s high enough to trigger effects, but not so high that the response fades or changes.
This study explored that idea directly: Which dose range produces the best pain-relief pattern, and does repeating sessions help?
What the study did (in simple terms)
Researchers induced localized inflammatory pain in mice and then applied Class 3B laser PBM once daily for five days, using different energy doses to compare effects.
They measured:
- Pain sensitivity (how strongly the paw reacted to light touch/pressure), using a standard test
- Swelling (paw edema) over time
PBM protocol summary (study parameters)
PBM was delivered using a Class 3B laser system with:
- 808 nm near-infrared light (200 mW)
- 637 nm red light (300 mW)
- Energy densities tested: 2 to 20 J/cm²
- Schedule: daily for 5 days
Key findings:
Pain sensitivity (main outcome)
- On the first day, PBM reduced pain sensitivity at 4, 8, and 12 J/cm².
- 8 J/cm² produced the most sustained pain-relief pattern.
- Repeating PBM daily at 4 and 8 J/cm² helped maintain reduced pain sensitivity across the five-day period.
Swelling (edema)
- PBM did not significantly reduce paw swelling, even when pain sensitivity improved.
Takeaway
This preclinical study suggests Class 3B laser PBM can reduce inflammatory pain sensitivity in a dose-dependent way, with the most reliable results at intermediate doses — especially when sessions are repeated daily. In this model, the therapy appeared to influence pain sensitivity more than swelling, which may be useful for understanding how PBM supports pain-related outcomes.
Reference: Cidral-Filho FJ, Bonotto NA, Oliveira BH, Dutra AR, Nazário J, Martins DF. Class 3B LASER PBM Produces a Joule-Response Dependent Analgesic Effect in CFA-Induced Inflammation. Presented at the IASP 2024 World Congress on Pain, Amsterdam.
Laser system: Avant Wellness LZ30 Pro Z.