RESUMO
We report the stress-strain effect of a stretchable natural rubber (NR)-calcium phosphate composite on the surface wettability (SW) using an innovative approach coupling a uniaxial tensile micromachine, goniometer, and microscope. In situ contact angle measurements in real time were performed during mechanical tension. Our results show that SW is guided by the stress-strain relationship with two different characteristics, depending on the static or dynamic experiments. The results evidenced the limits of the classical theory of wetting. Furthermore, based on the mechanically tunable SW of the system associated with the cytocompatibility of the NR composite, we have modeled such a system for application as a cell support. From the experimental surface energy value, our proposed 3D modeling numerical simulation predicted a window of opportunities for cell-NR survival under mechanical stimuli. The presented data and the thermodynamics-based theoretical approach enable not only accurate correlation of SW with mechanical properties of the NR composite but also provide huge potential for future cell supportability in view of tissue engineering.
RESUMO
Tendinopathy is a common disease with a variety of treatments and therapies. Laser therapy appears as an alternative treatment. Here, we investigate the effects of laser irradiation in an experimental model of tendinitis induced by collagenase injection on rats' Achilles tendon, verifying its action in important inflammatory markers. Male Wistar rats were used and divided into five groups: control saline (C), non-treated tendinitis (NT) and tendinitis treated with sodium diclofenac (D) or laser (1 J) and (3 J). The tendinitis was induced by collagenase (100 µg/tendon) on the Achilles tendon, which was removed for further analyses. The gene expression for COX-2; TNF-α; IL-6; and IL-10 (RT-PCR) was measured. The laser irradiation (660 nm, 100 mW, 3 J) used in the treatment of the tendinitis induced by collagenase in Achilles tendon in rats was effective in the reduction of important pro-inflammatory markers such as IL-6 and TNF-α, becoming a promising tool for the treatment of tendon diseases.
Assuntos
Tendão do Calcâneo/efeitos da radiação , Expressão Gênica/efeitos da radiação , Terapia com Luz de Baixa Intensidade , Tendinopatia/radioterapia , Tendão do Calcâneo/metabolismo , Tendão do Calcâneo/patologia , Animais , Anti-Inflamatórios não Esteroides/uso terapêutico , Colagenases , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Diclofenaco/uso terapêutico , Modelos Animais de Doenças , Interleucina-10/genética , Interleucina-10/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Masculino , Ratos , Ratos Wistar , Tendinopatia/induzido quimicamente , Tendinopatia/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
NSAIDs are widely prescribed and used over the years to treat tendon injuries despite its well-known long-term side effects. In the last years several animal and human trials have shown that low-level laser therapy (LLLT) presents modulatory effects on inflammatory markers, however the mechanisms involved are not fully understood. The aim of this study was to evaluate the short-term effects of LLLT or sodium diclofenac treatments on biochemical markers and biomechanical properties of inflamed Achilles tendons. Wistar rats Achilles tendons (n = 6/group) were injected with saline (control) or collagenase at peritendinous area of Achilles tendons. After 1 h animals were treated with two different doses of LLLT (810 nm, 1 and 3 J) at the sites of the injections, or with intramuscular sodium diclofenac. Regarding biochemical analyses, LLLT significantly decreased (p < 0.05) COX-2, TNF-α, MMP-3, MMP-9, and MMP-13 gene expression, as well as prostaglandin E(2) (PGE(2) ) production when compared to collagenase group. Interestingly, diclofenac treatment only decreased PGE(2) levels. Biomechanical properties were preserved in the laser-treated groups when compared to collagenase and diclofenac groups. We conclude that LLLT was able to reduce tendon inflammation and to preserve tendon resistance and elasticity.