Photobiomodulation of Matrix Metalloproteinases in Rat Calcaneal Tendons

• Published in: Photobiomodulation, photomedicine, and laser surgery Vol. 37; no. 7; p. 421
• Main Authors: Fernandes de Jesus, Julio, Spadacci-Morena, Diva Denelle, Rabelo, Nayra Deise Dos Anjos, Pinfildi, Carlos Eduardo, Fukuda, Thiago Yukio, Plapler, Helio
• Format: Journal Article
• Language: English
• Published: United States 01-07-2019
• Subjects: Achilles Tendon - metabolism; Animals; Disease Models, Animal; Low-Level Light Therapy - methods; Male; Matrix Metalloproteinase 1 - metabolism; Matrix Metalloproteinase 13 - metabolism; Matrix Metalloproteinase 3 - metabolism; Rats; Rats, Wistar; Tendinopathy - metabolism; Tendinopathy - radiotherapy; photobiomodulation; calcaneal tendon; inflammation; matrix metalloproteinases; tendinopathy
• ISSN: 2578-5478
• DOI: 10.1089/photob.2019.4633

The main objective was to verify the modulatory effects of MMP-1, MMP-3, and MMP-13 levels on the partially injured calcaneal tendons of rat exposure to photobiomodulation.
Photobiomodulation has been shown to have anti-inflammatory and regenerative effects on tendon injuries. However, there is still uncertainty regarding the beneficial effects in matrix metalloproteinase (MMP) levels, especially MMP-1, -3, and -13.
Sixty-five male Wistar rats were used. Sixty were submitted to a direct trauma on the calcaneal tendons and were randomly distributed into the following six groups: LASER 1, 3, and 7 (10 partially injured calcaneal tendons in each group treated with photobiomodulation for 1, 3, and 7 days, respectively) and Sham 1, 3, and 7 (same injury, with simulated photobiomodulation). The remaining five animals were allocated to the normal group (no injury or treatment procedure). The 780 nm low-level laser was applied with 70 mW of mean power and 17.5 J/cm
of fluency for 10 sec, once a day. The tendons were surgically removed and analyzed for MMP-1, MMP-3, and MMP-13 through immunohistochemistry.
MMP-3 levels remained close to normal in all experimental groups (
 > 0.05); however, reductions (
 < 0.05) in MMP-1 and MMP-13 levels were detected in the groups submitted to one, three, and seven low level laser therapy applications.
The photobiomodulation protocol was able to reduce MMP-1 and MMP-13 levels in injured calcaneal tendons.