The results of the present study indicate that LLLT was able to prevent bone loss after OVX in rats. However, further studies are needed to investigate the effects of different parameters, wavelengths, and sessions of applications on OVX rats.

The results of the present study indicate that photoradiation had stimulatory effects on femora of osteopenic rats, mainly at the dose of 120 J/cm.(2) However, further studies are needed to investigate the effects of different parameters, wavelengths, and sessions of applications on ovariectomized rats.

The aim of this study was to investigate the effects of low-level laser therapy (LLLT), 830 nm, on femora of exercised osteopenic rats. Sixty female rats were used, which were divided into six groups: sham-operated control, osteopenic control, sham-operated trained, osteopenic trained, sham-operated trained and irradiated, and osteopenic trained and irradiated. The exercise program and the laser irradiation were performed 48 h over an 8-week period. The exercise program was made in a container, filled with warm water, and consisted of jumps (four series, with ten jumps). The laser irradiation was performed with a Ga-Al-As laser, 830 nm, 100 W/cm2, 120 J/cm2. Femora were submitted to a physical and geometrical properties evaluation, a biomechanical test, and calcium and phosphorus evaluation. Exercised animals showed higher bone strength and physical properties values. However, the LLLT did not improve the stimulatory effects of the exercise on the osteopenic rats. The exercise program was able to increase femora strength and physical properties of osteopenic rats. However, concurrent treatments did not produce a more pronounced effect on femora.

Muitos estudos demonstram que programas de atividade física são eficazes para estimular o metabolismo ósseo, sendo utilizados como uma modalidade terapêutica em caso de perda óssea devido a osteoporose. Entretanto, vários pontos relacionados a intensidade e freqüência ideal para do exercício físico ainda não estão esclarecidos. Com isso, o objetivo deste estudo foi determinar os efeitos de um programa de exercícios físicos de alta intensidade na morfometria, na força óssea e no conteúdo mineral do fêmur de ratas osteopênicas. Foram utilizadas 40 ratas, distribuídas em 4 grupos: grupo intacto sedentário (SS); grupo osteopênico sedentário (OS); grupo intacto treinamento (ST) e grupo osteopênico treinamento (OT). O programa de exercício foi iniciado 8 semanas após a ovariectomia e foi realizado 3 vezes por semana, durante 8 semanas. Cada sessão foi constituída por 4 séries de 10 saltos cada. Após a eutanásia dos animais, os fêmures foram retirados e processados para as analises. RESULTADOS: os animais osteopênicos sedentários demonstraram uma diminuição da força óssea e uma diminuição dos pesos ósseos, da densidade óssea e do conteúdo de cálcio. As ratas osteopênicas exercitadas mostraram maiores valores na avaliação dos pesos ósseos, da força óssea, da densidade óssea e do conteúdo mineral, evidenciando o efeito positivo deste protocolo no metabolismo ósseo. Os resultados deste estudo indicam que a intensidade e a duração do programa de exercícios utilizado foi eficaz para produzir modificações nas propriedades geométricas e na forca óssea, nos fêmures das ratas osteopênicas, o que contribuiu para reverter as perdas ósseas após a ovariectomia.

Introduction Bioprinting facilitates highly-specific deposition of skin cells and biomaterials. Skin bioprinting is still limited by prolonged printing processes, poor mechanical properties and incomplete complexities. An important barrier is identifying an ideal hydrogel for skin bioprinting – one with a good balance between printing viable cells and producing robust scaffolds. Herein, three hydrogels were tested for potential use as bio-inks. Method A pneumatic-extrusion Inkredible 3D bioprinter was used. Initially, different concentrations of Alginate (reference), XG and Alginate/XG mixture were quantitatively evaluated for printability by calculating aspect ratio, square printability and cylinder height. The best two printable concentrations of each hydrogel were selected to undergo hDF viability testing to assess the effect of the printing process (Nozzle diameter and viscosity). The best concentration for each hydrogel group with best cell viability then underwent a 14-day hDF cytocompatibility testing period by using Live/dead staining, metabolic activity, dsDNA and collagen quantification. Result XG revealed a remarkable ability to build 3D shapes (XG(6%) with 27G nozzle-10.0mm±0.2 cylinder height). XG(6%), Alginate/XG(4%/10%) and Alginate(6%) were identified as the best concentrations to undergo 14-day cytocompatibility testing. XG(6%) and Alginate/XG(4%/10%) had better day 1 hDF viability (87.3%±2.9; 87.6%±1.5, respectively) than Alginate(6%)(74%±2.65). All hydrogels had gradually improving cell viability. Cell proliferation remained comparable amongst all hydrogels. Moreover, collagen production was confirmed in all constructs. Conclusion Bioprinted XG is cytocompatible with hDF still further optimisation of XG is required to prolong its degradability to optimise its application as a hydrogel for skin bioprinting. Abbrev XG–Xanthan gum; hDF–human Dermal Fibroblasts Take-home message There is still no ideal hydrogel identified for the purpose of skin bioprinting. An updated systematic review should be carried out to assess the current best available hydrogels.

Aim Despite several decades of research in tissue engineering, reconstructing a 3D human-sized ear that can stand the test of time has remained a challenge. Autologous cartilage reconstruction remains the main treatment choice despite the associated morbidity. Progress in the field has been made and several studies have used tissue-engineered implants in immunocompetent animals with promising results. Method This study critically reviews and assesses the characteristics that make auricular reconstruction so challenging and how far research has come in addressing the following: mechanical properties; vascularisation; immune response; cell sourcing; surgical attachments; allografts; and cost. Results The question is whether tissue engineering will realistically replace autologous cartilage reconstruction in the short-term, or will advances in other areas, outlined in this article, manage to provide suitable and aesthetically accurate scaffolds. Conclusions Advances in tissue engineering are slowly progressing and utilise advances in both biomaterial design and 3D bioprinting to try and address the challenges of auricular reconstruction. Tissue engineering is still a promising solution to auricular reconstruction but still requires further research before becoming a reality.