Laser acupuncture-induced analgesic effect and molecular alterations in an incision pain model: a comparison with electroacupuncture-induced effects.
Study Goal
The researchers aimed to investigate the effectiveness of Low-Level Laser Acupuncture (LLLA) in alleviating acute postincisional pain and compare its efficacy to electroacupuncture (EA).
Results Summary
All three LLLA treatments reduced mechanical pain (tactile allodynia) in the affected paw, with the 30-minute red laser treatment also improving pain in the contralateral paw and showing efficacy similar to EA. However, LLLA had minimal effect on heat hyperalgesia, and the 30-minute red laser group reversed increases in spinal cord markers linked to pain sensitization.
Population
Male adult rats with induced plantar incision pain.
Effective Dosage
GaAlAs laser irradiation (two red laser groups: 30- or 15-minute durations; one near-infrared laser group: 30-minute duration).
Duration
5 days (immediately post-operation and the following 4 days).
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Low-level laser acupuncture (LLLA) | neutral | photobiomodulation | - | - | produces | #1 |
Low-level laser acupuncture (LLLA) | neutral | an alternative to low-level laser therapy | - | - | is | #2 |
Low-level laser acupuncture (LLLA) | neutral | analgesic effect on chronic pain | - | - | has been proven | #3 |
All three LLLA treatments | decrease | post-PI tactile allodynia | Male adult rats | - | attenuated | #4 |
30-min red laser treatment | decrease | post-PI tactile allodynia in the contralateral paw | Male adult rats | - | affected | #5 |
30-min red laser treatment | neutral | electroacupuncture (EA) | Male adult rats | - | had similar efficacy to that of | #6 |
All laser treatments | decrease | heat hyperalgesia | Male adult rats | - | barely reduced | #7 |
30-min red laser group | decrease | PI-induced p-ERK expression in the spinal cord | Male adult rats | - | showed reversed increases of | #8 |
30-min red laser group | decrease | PI-induced p-p38 expression in the spinal cord | Male adult rats | - | showed reversed increases of | #9 |
30-min red laser group | decrease | PI-induced iNOS expression in the spinal cord | Male adult rats | - | showed reversed increases of | #10 |
30-min red laser group | no change | PI-induced TNF expression in the spinal cord | Male adult rats | - | did not show reversed increases of | #11 |
Repetitive LLLA treatments | decrease | PI-induced mechanical pain | Male adult rats | - | ameliorated | #12 |
Low-level laser acupuncture (LLLA) | neutral | EA as an adjuvant for postoperative pain control | - | - | is an alternative to | #13 |
Low-level laser acupuncture (LLLA) produces photobiomodulation through acupuncture point and is an alternative to low-level laser therapy. Although the analgesic effect of LLLA on chronic pain has been proven, its effect on acute postincisional pain has yet to be investigated. A plantar incision (PI) model was used to mimic human postsurgical pain. Male adult rats received GaAlAs laser irradiation at the right ST36 acupoint immediately after operation and on the following 4 days. Three laser treatment groups (two red laser groups with a 30- or 15-min treatment duration and one 30-min near-infrared laser group) were compared with sham LLLA and naive groups and an electroacupuncture (EA) group (separate study). Behavioral withdrawal thresholds of both hind paws were measured before and after incision. Expression of mitogen-activated protein kinases (p-ERK and p-p38), inducible nitric oxide synthase (iNOS), and tumor necrosis factor (TNF) in the spinal cord was analyzed. All three LLLA treatments attenuated post-PI tactile allodynia in the ipsilateral paw, but only the 30-min red laser treatment affected the contralateral paw and had similar efficacy to that of EA. All laser treatments barely reduced heat hyperalgesia in both hind paws. At 3 days after PI, the 30-min red laser group showed reversed increases of PI-induced p-ERK, p-p38, and iNOS but not TNF expression in the spinal cord. Repetitive LLLA treatments ameliorated PI-induced mechanical pain. The inhibition of multiple sensitization signals highlights the unique clinical role of LLLA. Thus, LLLA is an alternative to EA as an adjuvant for postoperative pain control.