Research Article: Effect of low intensity photobiomodulation associated with norbixin-based poly (hydroxybutyrate) membrane on post-tenotomy tendon repair. In vivo study1

Date Published: May 22, 2020

Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia

Author(s): Lízia Daniela e Silva Nascimento, Renata Amadei Nicolau, Antônio Luiz Martins Maia, Kárita Francisca e Silva Nascimento, José Zilton Lima Verde Santos, Rayssilane Cardoso de Sousa, Luiz Fernando Meneses Carvalho, Vicente Galber Freitas Viana.


To evaluate the in vivo response of photobiomodulation therapy associated with norbixin-based poly(hydroxybutyrate) membrane (PHB) in tenotomized calcaneal tendon.

Thirty rats were randomly allocated to six groups (n=5 each): LED groups (L1, L2 and L3) and membrane + LED groups (ML1, ML2 and ML3). The right calcaneal tendons of all animals were sectioned transversely and were irradiated with LED daily, one hour after surgery every 24 hours, until the day of euthanasia. At the end of the experiments the tendons were removed for histological analysis.

The histological analysis showed a significant reduction in inflammatory cells in the ML1, ML2 and ML3 groups (p=0.0056, p=0.0018 and p<0.0001, respectively) compared to those in the LED group. There was greater proliferation of fibroblasts in the ML1 (p<0.0001) and L3 (p<0.0001) groups. A higher concentration of type I collagen was also observed in the ML1 group (p=0.0043) replacing type III collagen. Photobiomodulation in association with norbixin-based PHB membrane led to control of the inflammatory process. However, it did not favor fibroblast proliferation and did not optimize type I collagen formation in the expected stage of the repair process.

Partial Text

Calcaneal tendon rupture is the most frequent tendon lesion in high physical activities of intensity sports such as running and jumping, affecting not only athletes, but also sedentary, and may limit the function and ability of patients to perform their activities of daily living, since it plays an important role in walking1–5. It affects young and middle-aged individuals more frequently, but recent studies have indicated its increasing incidence among active elderly4,6. Treatment options for this lesion include conservative and surgical (open or percutaneous) measures; however, these options are still controversial and debated in the scientific community regarding the recurrence of rupture and other complications4,7,8.

The increased incidence of chronic lesions of the calcaneus tendon observed in recent decades has been motivating studies that address therapeutic alternatives to improve and/or accelerate the repair of this condition16,26, since this lesion may result in severe functional impairment and a drastic reduction in quality of life27. In this context, studies that employed biocompatible membranes or photobiomodulation obtained promising results13,14,16,17. However, so far there has been no association between these techniques. Thus, this study aimed to associate the norbixin-based PHB membrane with LED therapy in the process of tendon repair.

The use of norbixin-based PHB membrane associated with low-intensity LED therapy in the treatment of total calcaneal tenotomy of rats reduced the levels of inflammatory infiltrate in the lesion. However, it did not favor the proliferation of fibroblasts in the first two weeks and did not optimize the formation of type I collagen in the expected stage of the repair process. The present study indicates that there was little effectiveness in the simultaneous use of the two therapeutic elements when compared to the isolated use of LED therapy.




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