Osteoarthritis (OA) is a chronic inflammatory disease and is characterized as a degenerative process. This study aimed to evaluate and compare the effects of a topical nonsteroidal anti-inflammatory drug (NSAID), physical activity, and photobiomodulation therapy (PBMT) applied alone and/or in combination between them in an experimental model of knee OA. OA was induced by injection of papain in the knees of rats. After 21 days, the animals started to be treated with the above treatment. Histological analysis shows that the experimental model of OA induction causes morphological changes consistent with the disease, and among treatments, the PBMT is the most effective for reducing these changes. Moreover, the results demonstrate that PBMT and NSAID reduce the total number of cells in the inflammatory infiltrate (p<0.05) and PBMT was the most effective for reducing the activity of myeloperoxidase (p<0.05). Finally, we observed that both NSAID and PBMT were effective for reducing the gene expression of MMP-3 (p<0.05), but in relation to the gene expression of MMP-13, PBMT was the most effective treatment (p<0.05). The results of this study indicate that PBMT is the most effective therapy in stopping disease progression, and improving inflammatory conditions observed in OA.
Objective: Concomitant use of multiple therapies is common in musculoskeletal and airway disorders. Low
level laser therapy (LLLT) is considered a promising therapy in arthritis, tendinopathies and rhinitis. We
designed two animal studies to assess if the expected anti-inflammatory effect LLLT could be affected by
resection of the adrenal gland or concomitant use of the cortisol antagonist mifepristone.
Methods: Two studies were performed, with 40 male Wistar rats and with 40 Balb C male mice respectively..
In both studies, four groups received carrageenan and one control group received saline. At 1, 2, and 3 hours
after injections, LLLT irradiation was performed with a dose of 7.5 J/cm<sup>2</sup>. In the rat study, two of the
carrageenan groups had the adrenal gland dissected. In the mice study, two of the carrageenan-injected groups
were in addition pre-treated with orally administered mifepristone.
Results: In the rat paw study, LLLT reduced edema significantly compared to the carrageenan only group (1.5
vs 0.9 ml, p< 0.05), but LLLT failed to inhibit edema formation in the group which had the adrenal gland
resected. In carrageenan-induced pleurisy, LLLT significantly reduced the number of leukocyte cells ( p<0.0001,
Mean 34.5 [95%CI: 32.8 - 36.2] versus 87.7 [95%CI: 81.0 - 94.4]), and that the effect of LLLT could be totally
blocked by adding the cortisol antagonist mifepristone ( p<0.0001, Mean 34.5 [95%CI: 32.1 - 36.9] versus 82.9
[95%CI: 70.5 - 95.3]).
Conclusion: Steroid therapy should not be used concomitantly with LLLT, as the anti-inflammatory effect of
LLLT is lost if cortisol receptors are downregulated.
<b>Objective:</b> Low level laser therapy (LLLT) has been forwarded as therapy for osteoarthritis and tendinopathy.
Results in animal and cell studies suggest that LLLT may act through a biological mechanism of inflammatory
modulation. The current study was designed to investigate if LLLT has an anti-inflammatory effect on activated
tendinitis of the Achilles tendon.
<b>Methods:</b> Seven patients with bilateral Achilles tendonitis (14 tendons) who had aggravated symptoms by
pain-inducing activity immediately prior to the study. LLLT (1.8 Joules for each of three points along the
Achilles tendon with 904nm infrared laser) and placebo LLLT were administered to either Achilles tendons in a
random order to which patients and therapist were blinded. Inflammation was examined by 1) mini-invasive
microdialysis for measuring the concentration of inflammatory marker PGE<sub>2</sub> in the peritendinous tissue, 2)
ultrasound with Doppler measurement of peri- and intratendinous blood flow, 3) pressure pain algometry and 4)
single hop test.
<b>Results:</b> PGE<sub>2-</sub> levels were significantly reduced at 75, 90 and 105 minutes after active LLLT compared both to
pre-treatment levels (p=0.026) and to placebo LLLT (p=0.009). Changes in pressure pain threshold (PPT) were
significantly different (P=0.012) between groups. PPT increased by a mean value of 0.19 kg/cm<sup>2</sup> [95%CI:0.04 to
0.34] after treatment in the active LLLT group, while pressure pain threshold was reduced by -0.20 kg/cm<sup>2</sup>
[95%CI:-0.45 to 0.05] after placebo LLLT.
<b>Conclusion:</b> LLLT can be used to reduce inflammatory musculskeletal pain as it reduces inflammation and
increases pressure pain threshold levels in activity-induced pain episodes of Achilles tendinopathy.