Effect of photobiomodulation on expression of IL-1β in skeletal muscle following acute injury

Abstract

Muscle repair is regulated by growth factors and cytokines. Low-level laser therapy (LLLT) seems to influence acute inflammation and accelerate skeletal muscle repair. This study verifies the effect of LLLT on the expression of IL-1β in the tibialis anterior (TA) muscle of rats following acute injury. Wistar rats (n=35) were allocated into three groups: control (without lesion and LLLT, n=5), injury group (n=15), and injury + LLLT group (n=15). The acute injury was induced by the contact with a cooled metal probe (3 mm in diameter) during 10 s, twice, in the same muscle area. LLLT was used three times a week using the InGaAlP laser (660 nm; beam spot of 0.04 cm(2), output power of 20 mW, power density of 500 mW/cm(2), and energy density of 5 J/cm(2) during 10 s). The animals were analyzed at 1, 7, and 14 days following injury. TA muscles samples were used for obtaining total RNA and performing cDNA synthesis. Real-time polymerase chain reactions were realized using IL-1β primer. There was a decrease in IL-1β expression after 7 days in LLLT group in comparison with the no treated group. In conclusion, LLLT was able to decrease IL-1β expression during the skeletal muscle repair following an acute injury.

Photobiomodulation and different macrophages phenotypes during muscle tissue repair

“…Cryoinjury, which can be considered an acute injury1, 12, 13, 16, 17, 21 provoked myonecrosis and the infiltration of inflammatory cells in the injured area on Day 2. A large number of CD68 + macrophages (M1) and small number of CD206 + and CD163 + (M2) macrophages were also found 2 days after injury, which is in accordance with previous descriptions (for review, see1).…”

“…The laser beam was applied in contact with the skin surface over the cryoinjury area at an angle of 90° between the emitter and skin to prevent reflection. Irradiation was applied to 8 points (Figure S2B) surrounding the sutured area 12, 16, 17, 18. After 2, 4 and 7 days of treatment, the animals were weighed and euthanized with an overdose of anesthesia (240 mg/kg of ketamine and 30 mg/kg of xylazine).…”

“…In a time‐dependent manner, red and NIR therapies are also able to modulate the gene expression of mediators, such as TNF‐ α , 15, 16 IL1‐ β , 17 IL‐6 18 and TGF‐ β16, 19 as well as genes involved in the differentiation of myogenic stem cells, such as MyoD 18, 20 and myogenin 18, 20 during the muscle repair process.…”

Low level laser therapy on injured rat muscle

“…Albertini et al [28] observed decreased mRNA expression, for TNF-α and IL-1β, 3 hours after irradiation with wavelengths of 660 and 684 nm at a dose of 7.5 J/cm 2 , in inflammation induced by carrageenan injection in subplantar muscle tissue of rat paws. Using a cryoinjury model of inflammation, Fernandes et al [29] observed a significant decrease in IL-1β mRNA expression 7 days after injury, in LLLT treated (660 nm, 5 J/cm 2 ) rats.…”

Low level laser therapy on injured rat muscle: assessment of irradiation parameters

“…Local reduction of these cytokines, measured by mRNA expression, was reported in irradiated injured muscle tissue, using red laser irradiation (660 and 684 nm, with doses between 5 and 7.5 J/cm 2 . [21,22] Systemic measurements of these cytokines can also evaluate LLLT effectiveness, since optical radiation can induce changes in the cytokine content of blood [23,24].…”