Effect of phototherapy with light-emitting diodes (890 nm) on tendon repair: an experimental model in sheep

Large animal models for the study of tendinopathy

Tendinopathy has a high incidence in athletes and the aging population. It can cause pain and movement disorders, and is one of the most difficult problems in orthopedics. Animal models of tendinopathy provide potentially efficient and effective means to develop understanding of human tendinopathy and its underlying pathological mechanisms and treatments. The selection of preclinical models is essential to ensure the successful translation of effective and innovative treatments into clinical practice. Large animals can be used in both micro- and macro-level research owing to their similarity to humans in size, structure, and function. This article reviews the application of large animal models in tendinopathy regarding injuries to four tendons: rotator cuff, patellar ligament, Achilles tendon, and flexor tendon. The advantages and disadvantages of studying tendinopathy with large animal models are summarized. It is hoped that, with further development of animal models of tendinopathy, new strategies for the prevention and treatment of tendinopathy in humans will be developed.

Effect of norbixin-based poly(hydroxybutyrate) membranes on the tendon repair process after tenotomy in rats

Purpose:

To determine the efficacy of norbixin-based poly(hydroxybutyrate) (PHB) membranes for Achilles tendon repair.

Methods:

Thirty rats were submitted to total tenotomy surgery of the right Achilles tendon and divided into two groups (control and membrane; n = 15 each), which were further subdivided into three subgroups (days 7, 14, and 21; n = 5 each). Samples were analyzed histologically.

Results:

Histological analysis showed a significant reduction in inflammatory infiltrates on days 7, 14 (p < 0.0001 for both), and 21 (p = 0.0004) in the membrane group compared to that in the control group. There was also a significant decrease in the number of fibroblasts in the control group on days 7, 14 (p < 0.0001), and 21 (p = 0.0032). Further, an increase in type I collagen deposition was observed in the membrane group compared to that in the control group on days 7 (p = 0.0133) and 14 (p = 0.0107).

Conclusion:

Treatment with norbixin-based PHB membranes reduces the inflammatory response, increases fibroblast proliferation, and improves collagen production in the tendon repair region, especially between days 7 and 14.

Effects of Therapy with Light Emitting Diode (LED) in the Calcaneal Tendon Lesions of Rats: A Literature Review

The objective of this review was to analyze original articles about the effects of therapy with LED in experimental models of calcaneal tendon lesions of rats. The search was performed in the period from February to May 2018, in the following electronic databases: MEDLINE, SciELO, and LILACS, besides the Google Scholar, using the descriptors “Achilles tendon”, “Rats”, “LED”, “Tendinopathy”, and “Low-level Light Therapy”, as well as their matching parts in the Portuguese and Spanish languages, related to and in association with the relevant terms to the content sought. From the descriptors used 215 works were found. After application of eligibility criteria 8 works were selected, in which positive results were found after the application of the LED. Regarding the main results found with phototherapy, we observed a significant reduction in inflammation. Only one article mentioned little reduction of inflammation. In relation to the number of sessions, there was wide variation, with an average of approximately 5 sessions every 24 hours. Studies in this review pointed out, therefore, positive results in the repair of the calcaneal tendon after therapy with irradiation LED; however, carrying out more experimental studies that help the standardization of parameters to be used in this therapy for further clinical studies becomes necessary.

Effect of light-emitting diodes, platelet-rich plasma, and their combination on the activity of sheep tenocytes

Healthy tendons play an important role in joint movements and subjected to a group of pathologies called tendinopathy due to multiple factors. Tendons have a slowly repairing process due to the low vascularity and cellularity. Treatment options aimed at potentiating the healing response and relieving symptoms. Phototherapy and platelet-rich plasma were novel treatment modalities in tendons based on photobiomodulation and growth factors during healing, and the results were encouraging suggesting calibrating treatment parameters. This study utilizes cell culture to explore the potential effect of light-emitting diode and/or growth factors in the form of platelet-rich plasma (PRP) on the activity of tenocytes isolated from sheep Achilles tendons by measuring the cell metabolism and cell mobility using cell viability and migration assays to proof safety and confirm activity. Results showed that sheep tenocyte-cultured groups treated with 5% platelet-rich plasma alone or combined with 4 J/cm² light-emitting diode have increased viability significantly when compared to control group after a 48 h, while light-emitting diode treatment has not decreased cell migration significantly when compared with control. Result suggests that using platelet-rich plasma alone or combined with light-emitting diode might have potential to enhance healing response at the conditions applied. PRP could enhance proliferation while LED could enhance migration and proliferation. Further research is needed at longer durations.

EFICÁCIA DA FONOFORESE COM XIMENIA AMERICANA L. NA INFLAMAÇÃO DE TENDÃO DE RATOS

RESUMO Introdução: Diversos recursos terapêuticos, como laser e ultrassom isolado, combinados com fármacos e fonoforese têm sido utilizados em casos de inflamação e reparo de tendão, sendo o ultrassom pulsado bastante eficaz em tendinites crônicas. Objetivo: Analisar a eficácia do uso da fonoforese com o extrato etanólico das cascas do caule da Ximenia americana L. na resolução do processo inflamatório crônico em Rattus norvegicus. Métodos: A amostra consistiu em 120 animais para análise da resposta inflamatória, utilizando-se como variáveis edema, força biomecânica, número de fibroblastos e análise histológica. Resultados: Nos 7° e no 14° dia, verificou-se diferença significativa entre o grupo ultrassom com gel do caule de Ximenia americana L. e o grupo ultrassom com placebo (p < 0,05) quanto à redução de edema, aumento da força máxima de ruptura, redução extremamente significativa da deformação máxima (p < 0,001), além de aumento dos fibroblastos. Na análise histológica, houve melhora do processo inflamatório inicial e aceleração do reparo tendíneo, com redução de células inflamatórias e com deposição de colágeno organizado com matriz extracelular densa. Conclusão: O ultrassom pulsado combinado com o gel do caule de Ximenia americana L. é uma forma terapêutica eficaz para a resolução do processo inflamatório crônico.

Transdentinal photobiostimulation of stem cells from human exfoliated primary teeth

AIM

To evaluate the effects of infrared light-emitting diode (LED) irradiation on stem cells from human exfoliated deciduous teeth (SHEDs).

METHODOLOGY

Exfoliated primary teeth were obtained (n = 3), and SHEDs obtained from the teeth were seeded on the pulpal surface of 0.2-mm-thick dentine discs produced from permanent molars. The cells were incubated for 24 h by placing the discs in plain Dulbecco's modified Eagle's medium (DMEM). The DMEM was then replaced with new culture medium formulated for odontoblast differentiation. After 12 h in the second medium, SHEDs were irradiated through the dentine discs using an infrared LED (850 nm) with a power density of 80 mW cm^-2 . Energy doses (EDs) delivered to the occlusal surface of the dentine discs were 0 (control), 2 and 4 J cm^-2 (n = 6). Subsequent tests were performed 72 h after irradiation. These tests included cell viability (MTT), alkaline phosphatase activity (ALP), total protein production (TP), scanning electron microscopy (SEM), as well as gene expression for ALP, Col I, DSPP and DMP-1. Data were analysed using Kruskal-Wallis and Mann-Whitney t-tests (α = 0.05).

RESULTS

Both EDs (2 and 4 J cm^-2 ) significantly increased cell viability and ALP activity. For TP, ALP and Col I gene expression, only the 4 J cm^-2 group had significantly higher values compared to the control group. Cell morphology was not affected by irradiation.

CONCLUSION

Infrared LED irradiation was capable of biostimulating SHEDs through a 0.2 mm thickness of dentine, especially at the 4 J cm^-2 level.

Effects of low-intensity non-coherent light therapy on the inflammatory process in the calcaneal tendon of ovariectomized rats

The aim of this experimental study was to investigate the effects of low-intensity light-emitting diode (LED) phototherapy on the inflammatory process in the calcaneal tendon of ovariectomized rats (OVX) through the involvement of the inflammatory mediators interleukin (IL)-6, IL-10, and tumor necrosis factor-alpha (TNF-α). Thirty-five female Wistar rats were divided into 4 groups: 3 groups of OVX rats totaling 30 rats (untreated OVX rats [OVX injury group], treated OVX rats [OVX LED group], and control OVX rats; subgroups existed based on the sampling times, which were 3, 7, and 14 days) and 1 group of non-OVX rats (not OVX; n = 5). Tendon injury was induced by trauma using a 208-g mass placed at 20 cm from the right tendon of each animal with energy of 0.70 J. The animals were treated 12 h after tendonitis with LED therapy and every 48 h thereafter until euthanasia (at 3, 7, or 14 days). The tendons were dissected and stored in liquid nitrogen at -196 °C, thawed only at the time of immunoenzymatic testing (ELISA). Groups treated with LED showed a decrease in the number of pro-inflammatory cells, IL-6, and TNF-α (p <0.05), and an increase in IL-10 (p < 0.05) when compared to the not OVX group (p < 0.05). It was concluded that low-intensity LED treatment using the parameters and wavelength of 945 nm in the time periods studied reduced the release of IL-6 and TNF-α and increased the release of IL-10, thereby improving the inflammatory response in OVX rats.

Flexor Tendon Injuries and Treatment Results of 67 Patients

Flexor tendon injury is the most commonly seen hand injury. Tendons are the structures which enable the muscles to adhere to the bones and transmit the movement starting from the muscle to the bones. They have significant role in hand movement. As treatment method, surgical repair: (1) Primary repair, (2) Secondary repair; techniques are used. With the scientific studies conducted, flexor tendon morphology, kinematics, biomechanics, biological properties and tendon improvement became quite understandable, good suturing materials were developed and consequently successful studies regarding primary repair results were published. Flexor tendon surgery has reached its current level with the accumulation of knowledge obtained from the increased clinical and experimental studies. This study addresses flexor tendon injuries and surgical treatment methods. We achieved 76.12% full functioning fingers in the results; we obtained following the physical treatment application that started on the 10th day after primary repair that we performed in 67 patients who applied with acute flexor tendon Zone 1-2 and 3 incision. Flexion restriction and contracture developed in 16 patients (23.88%) at various levels. Scar softening and revision surgery for contracture excision was performed in 8 patients (11.94%) with Zone 2 injury due to contracture. Superficial skin infection developed in 21 patients (31.34%) and was treated. Revision surgery was performed in 6 patients with Zone 1 injury due to rupture occurred during rehabilitation.