Low level laser therapy partially restores trachea muscle relaxation response in rats with tumor necrosis factor alpha-mediated smooth airway muscle dysfunction.
OBJECTIVE
It is unknown if the decreased ability to relax airway smooth muscles in asthma and other inflammatory airways disorders can be influenced by low level laser therapy (LLLT) irradiation. To investigate if LLLT could reduce impairment in inflamed trachea smooth muscles (TSM) in rats.


METHODS
Controlled rat study where trachea was dissected and mounted in an organ bath apparatus with or without a TNF-alpha solution.


RESULTS
Low level laser therapy administered perpendicularly to a point in the middle of the dissected trachea with a wavelength of 655 nm and a dose of 2.6 J/cm(2), partially restored TSM relaxation response to isoproterenol. Tension reduction was 47.0 % (+/-2.85) in the laser-irradiated group compared to 22.0% (+/-2.21) in the control group (P < 0.01). Accumulation of cAMP was almost normalized after LLLT at 22.3 pmol/mg (+/-2.1) compared to 17.6 pmol/mg (+/-2.1) in the non-irradiated control group (P < 0.01).


CONCLUSIONS
Low level laser therapy partially restores the normal relaxation response in inflamed TSM and normalizes accumulation of cAMP in the presence of isoproterenol.
Aimbire
F
F
Institute of Research and Development-IP&D/UNIVAP Av., Shsima Hifumi 2911, 12240-000 São José dos Campos, São Paulo, Brazil.
Bjordal
J M
JM
Iversen
V V
VV
Albertini
R
R
Frigo
L
L
Pacheco
M T T
MT
Castro-Faria-Neto
H C
HC
Chavantes
M C
MC
Labat
R M
RM
Lopes-Martins
R A B
RA
D000818:Animals; D066298:In Vitro Techniques; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D009126:Muscle Relaxation / Q000528:radiation effects*; D009130:Muscle, Smooth / Q000528:radiation effects*; D051381:Rats; D017208:Rats, Wistar; D014132:Trachea / Q000528:radiation effects*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D014409:Tumor Necrosis Factor-alpha