Comparative analysis of two low-level laser doses on the expression of inflammatory mediators and on neutrophils and macrophages in acute joint inflammation

Abstract

Synovial membrane inflammation plays an important role in osteoarthritis (OA) pathophysiology. The synovial tissue of patients with initial OA is characterized by mononuclear cell infiltration and the production of pro-inflammatory cytokines and other mediators of joint injury. The study aims to evaluate the effect of low-level laser therapy (LLLT) at doses of 2 and 4 J on joint inflammation in rats induced by papain through histopathological analysis, differential counts of inflammatory cells; gene expression of IL-1β, IL-6, and IL-10; and TNF-α protein expression. Male Wistar rats (20) were randomly divided (5 animals each) into a negative control group, an inflammation injury positive control group, a 2-J LLLT group subjected to injury and treated with 2 J of LLLT, and a 4-J LLLT group subjected to injury and treated with 4 J of LLLT. The animals were subjected to joint inflammation (4 % papain solution) and treated with LLLT. On the day of euthanasia, articular lavage was collected and centrifuged. The supernatant was analyzed for TNF-α protein expression by ELISA and IL-1β, IL-6, and IL-10 mRNA by RT-PCR. The joint tissue was also examined histologically. ANOVA with Tukey's post hoc test was used for comparisons. All data were expressed as means ± S.D. (p < 0.05). Both laser modalities were efficient in reducing cellular inflammation and decreasing the expression of IL-1β and IL-6. However, the 2-J treatment led to more reduction in TNF-α than the 4-J treatment. A single application of LLLT with 2 J was more efficient in modulating inflammatory mediators and inflammatory cells.

The Fluence Effects of Low-Level Laser Therapy on Inflammation, Fibroblast-Like Synoviocytes, and Synovial Apoptosis in Rats with Adjuvant-Induced Arthritis

“…16 An 808 nm AsGaAl laser at doses of 2 and 4 J can reduce the numbers of inflammatory cells (neutrophils and macrophages), TNF-a protein expression, as well as IL1b and IL-6 mRNA expression on joint inflammation in rats induced by papain. 10 These results also indicated a higher efficiency for the 2 J laser irradiation in attenuating the general inflammatory process, in particular with regard to the expression of TNF-a and the migration of neutrophils during the initial inflammatory phase of osteoarthritis. 10 A 660 nm InGaAIP laser at 2.5 J/cm 2 , which immediately irradiated 1 and 2 h after zymosan administration, significantly inhibited leukocytes influx and the release of IL-1 and IL-6 into the joint cavity on acute zymosan-induced arthritis in rats.…”

“…10 These results also indicated a higher efficiency for the 2 J laser irradiation in attenuating the general inflammatory process, in particular with regard to the expression of TNF-a and the migration of neutrophils during the initial inflammatory phase of osteoarthritis. 10 A 660 nm InGaAIP laser at 2.5 J/cm 2 , which immediately irradiated 1 and 2 h after zymosan administration, significantly inhibited leukocytes influx and the release of IL-1 and IL-6 into the joint cavity on acute zymosan-induced arthritis in rats. 18 However, in the other experimental study, a 660 nm LLLT with higher energy density, 214 J /cm 2 , which irradiated at the 72th h after tenotomy of the Achilles tendon, also significantly reduced the IL-6 level, but not IL-1 in the acute phase of inflammation in rats.…”

“…10,[14][15][16][17] An 810 nm LLLT at 5 J/cm 2 can decrease the mRNA levels of TNF-a and IL-1b in FLS from RA patients. 17 Also an 810 nm LLLT with 50, 150, and 300 J/cm 2 was able to inhibit the total numbers of leukocytes and mononuclear cells, as well as mRNA levels of IL-6 and IL-1 in rats with carrageenan-induced knee arthritis.…”

“…joint inflammation situations. [8][9][10] It can modulate proinflammatory mediators, thereby decreasing the expression of cytokines such as IL-1b, IL-6, and TNF-a, and it also can decrease the number of inflammatory cells (macrophages and neutrophils). 8,11 LLLT was introduced as an alternative noninvasive treatment for RA approximately two decades ago.…”

Reduction in Pain and Inflammation Associated With Chronic Low Back Pain With the Use of the Medical Food Theramine

“…Because IL-6 has been associated with the generation and propagation of chronic inflammation, it was selected as a marker in the study. Proinflammatory cytokines from acute inflammation promote neutrophil build up and the release of IL-6 45 . In the study, IL-6 followed the same pattern as CRP, with an increase in level of IL-6 in the ibuprofen-alone group (12.65%), a drop in IL-6 level in the AAB-alone group (23.55%), and a drop in the level of IL-6 in the AAB and ibuprofen group (43.1%).…”