Kelly Rosseti Fernandes

Aerobic exercise training and low-level laser therapy modulate inflammatory response and degenerative process in an experimental model of knee osteoarthritis in rats

OBJECTIVE The aim of this study was to evaluate the effects of an aerobic exercise training and low-level laser therapy (LLLT) (associated or not) on degenerative modifications and inflammatory mediators on the articular cartilage using an experimental model of knee OA. MATERIAL AND METHODS Fifty male Wistar rats were randomly divided into five groups: control group (CG); knee OA control group (OAC); OA plus exercise training group (OAT); OA plus LLLT group (OAL); OA plus exercise training associated with LLLT group (OATL). The exercise training (treadmill; 16 m/min; 50 min/day) and the laser irradiation (two points-medial and lateral side of the left joint; 24 sessions) started 4 weeks after the surgery, 3 days/week for 8 weeks. RESULTS The results showed that all treated groups showed (irradiated or not) a better pattern of tissue organization, with less fibrillation and irregularities along the articular surface and chondrocytes organization, a lower degenerative process measured by OARSI score and higher thickness values. Additionally, all treated group showed a reduced expression in IL-1β, caspase-3 and MMP-13 compared to OAC. Moreover, a lower caspase-3 expression was observed in OATL compared to OAL and OAT. CONCLUSION These results suggest that exercise training and LLLT were effective in preventing cartilage degeneration and modulating inflammatory process induced by knee OA.

Characterization and biocompatibility of a fibrous glassy scaffold

Bioactive glasses (BGs) are known for their ability to bond to living bone and cartilage. In general, they are readily available in powder and monolithic forms, which are not ideal for the optimal filling of bone defects with irregular shapes. In this context, the development of BG‐based scaffolds containing flexible fibres is a relevant approach to improve the performance of BGs. This study is aimed at characterizing a new, highly porous, fibrous glassy scaffold and evaluating its in vitro and in vivo biocompatibility. The developed scaffolds were characterized in terms of porosity, mineralization and morphological features. Additionally, fibroblast and osteoblast cells were seeded in contact with extracts of the scaffolds to assess cell proliferation and genotoxicity after 24, 72 and 144 h. Finally, scaffolds were placed subcutaneously in rats for 15, 30 and 60 days. The scaffolds presented interconnected porous structures, and the precursor bioglass could mineralize a hydroxyapatite (HCA) layer in simulated body fluid (SBF) after only 12 h. The biomaterial elicited increased fibroblast and osteoblast cell proliferation, and no DNA damage was observed. The in vivo experiment showed degradation of the biomaterial over time, with soft tissue ingrowth into the degraded area and the presence of multinucleated giant cells around the implant. At day 60, the scaffolds were almost completely degraded and an organized granulation tissue filled the area. The results highlight the potential of this fibrous, glassy material for bone regeneration, due to its bioactive properties, non‐cytotoxicity and biocompatibility. Future investigations should focus on translating these findings to orthotopic applications. Copyright

Comparative study of the effects of low-level laser and low-intensity ultrasound associated with Biosilicate® on the process of bone repair in the rat tibia

Objective: Verify the effects of the association between Biosilicate® and ultrasound and, Biosilicate® and laser in bone consolidation process of rats, through the biomechanical and histological analysis. Methods: Forthy male rats were used. The animals were randomized into four groups (n=10): control group fracture no treated (CGF); group treated with Biosilicate® (BG); group treated with Biosilicate® and laser (BLG); group treated with Biosilicate® and ultrasound (BUG). Results: The biomechanical analysis showed no significant difference among any groups after 14 days post-surgery. In the morphometric analysis, the control group showed moderate presence of new formed bone tissue inside the defects areas and the Biosilicate® group showed similar results. Despite those facts, the biomaterial osteogenic potential was demonstrated by the great amount of cells and bone tissue around the particles. Curiously, the Biosilicate® plus laser or ultrasound groups showed lower amounts of bone tissue deposition when compared with control fracture and Biosilicate® groups. Conclusion: The data from this study can conclude that Biosilicate® was able to accelerate and optimized the bone consolidation, through the modulation of the inflammatory process and the stimulation of new bone formation. However, when resources were associated, there are no positive results.

Comparação dos efeitos do laser de baixa potência e do ultrassom de baixa intensidade associado ao Biosilicato® no processo de reparo ósseo em tíbias de ratos

OBJECTIVE: Verify the effects of the association between Biosilicate® and ultrasound and, Biosilicate® and laser in bone consolidation process of rats, through the biomechanical and histological analysis. METHODS: Forthy male rats were used. The animals were randomized into four groups (n=10): control group fracture no treated (CGF); group treated with Biosilicate® (BG); group treated with Biosilicate® and laser (BLG); group treated with Biosilicate® and ultrasound (BUG). RESULTS: The biomechanical analysis showed no significant difference among any groups after 14 days post-surgery. In the morphometric analysis, the control group showed moderate presence of new formed bone tissue inside the defects areas and the Biosilicate® group showed similar results. Despite those facts, the biomaterial osteogenic potential was demonstrated by the great amount of cells and bone tissue around the particles. Curiously, the Biosilicate® plus laser or ultrasound groups showed lower amounts of bone tissue deposition when compared with control fracture and Biosilicate® groups. CONCLUSION: The data from this study can conclude that Biosilicate® was able to accelerate and optimized the bone consolidation, through the modulation of the inflammatory process and the stimulation of new bone formation. However, when resources were associated, there are no positive results.

Helium-neon laser therapy interferes with epiphyseal plate growth in the femur and tibia of rabbits

Abstract The purpose of this study was to evaluate the influence of low-level laser therapy (LLLT) on epiphyseal cartilage in the femur and tibia of rabbits. A total of six male New Zealand rabbits were used in this study. The right tibia or femur lesions (control group) served as negative control and the left as experimental (laser) group. Helium-neon (HeNe) laser light with an energy density of 6 J/cm2 and wavelength of 632.8 nm was applied to the left knees (laser group) over a period of 1, 3 and 5 weeks. All sections were analyzed using hematoxylin and eosin stained sections, and thickness of the resting, proliferative and hypertrophic and degenerative layers were measured. The results showed that the epiphyseal cartilage zones could be easily identified in both groups (control and laser). The measurements of epiphyseal plate showed no statistically significant differences (p>0.05) between control and experimental groups. Nevertheless, when each zone of the femur and tibia was analyzed, resting and proliferative layers decreased in both bones with laser application, showing statistically significant differences (p<0.05) for all weeks analyzed at this setting. Taken together, these results suggest that HeNe laser stimulates the cartilage ossification to bone, causing some delay in growth and development of the epiphyseal plate. Zusammenfassung Der Zweck dieser Studie war es, den Einfluss der Low-Level-Lasertherapie (LLLT) auf Epiphysenknorpel im Oberschenkelknochen und Schienbein von Kaninchen zu bewerten. In der Studie wurden insgesamt sechs männliche Neuseeland-Kaninchen verwendet. Die rechten Tibia- oder Femur-Läsionen (Kontrollgruppe) dienten als negative Kontrolle, die linken als experimentelle (Laser-) Gruppe. In der Laser-Gruppe wurden die linken Knie der Versuchstiere über einen Zeitraum von 1, 3 und 5 Wochen mit Helium-Neon-(HeNe)-Laserlicht (Energiedichte: 6 J/cm2, Wellenlänge: 632,8 nm) bestrahlt. Nach Beendigung der Versuchsreihe wurden mit Hämatoxylin und Eosin gefärbte Schnitte angefertigt und die Dicke der ruhenden, proliferativen und hypertrophen sowie degenerativen Schichten gemessen. Die Ergebnisse zeigten, dass die Epiphysenknorpel-Zonen leicht in beiden Gruppen identifiziert werden konnten (Kontroll- und Laser-Gruppe). Die Messungen der Epiphysenfuge zeigte keine statistisch signifikanten Unterschiede (p>0,05) zwischen Kontroll- und Laser-Gruppen. Dennoch, betrachtet man jeden Bereich des Oberschenkels und des Schienbeins, so verringerte sich mit der Laseranwendung die Dicke der ruhenden und proliferativen Schichten in beiden Knochen, wobei statistisch signifikante Unterschiede (p<0,05) für alle untersuchten Zeitabstände (1, 3 und 5 Wochen) festgestellt wurden. Zusammengenommen deuten diese Ergebnisse darauf hin, dass eine HeNe-Laserbestrahlung eine Knorpelverknöcherung stimuliert, was zu einer Verzögerung des Wachstums und der Entwicklung der Epiphysenfuge führen kann.

Biosilicate/PLGA osteogenic effects modulated by laser therapy: In vitro and in vivo studies

The main purpose of the present work was to evaluate if low laser level therapy (LLLT) can improve the effects of Biosilicate®/PLGA (BS/PLGA) composites on cell viability and bone consolidation using a tibial defects of rats. The composites were characterized by scanning electron microscope (SEM) and reflection Fourier transform infrared spectrometer (FTIR). For the in vitro study, fibroblast and osteoblast cells were seeded in the extract of the composites irradiated or not with LLLT (Ga-Al-As, 808nm, 10J/cm2) to assess cell viability after 24, 48 and 72h. For the in vivo study, 80 Wistar rats with tibial bone defects were distributed into 4 groups (BS; BS+LLLT; BS/PLGA and BS/PLGA+LLLT) and euthanized after 2 and 6weeks. Laser irradiation Ga-Al-As (808nm, 30J/cm2) in the rats was performed 3 times a week. The SEM and FTIR results revealed that PLGA were successfully inserted into BS and the microparticles degraded over time. The in vitro findings demonstrated higher fibroblast viability in both BS/PLGA groups after 24h and higher osteoblast viability in BS/PLGA+LLLT in all periods. As a conclusion, animals treated with BS/PLGA+LLLT demonstrated an improved material degradation and an increased amount of granulation tissue and newly formed bone.

Calcium phosphate fibers coated with collagen: In vivo evaluation of the effects on bone repair.

The aim of this study was to assess the characteristics of the CaP/Col composites, in powder and fiber form, via scanning electron microscopy (SEM), pH and calcium release evaluation after immersion in SBF and to evaluate the performance of these materials on the bone repair process in a tibial bone defect model. For this, four different formulations (CaP powder - CaPp, CaP powder with collagen - CaPp/Col, CaP fibers - CaPf and CaP fibers with collagen - CaPf/Col) were developed. SEM images indicated that both material forms were successfully coated with collagen and that CaPp and CaPf presented HCA precursor crystals on their surface. Although presenting different forms, FTIR analysis indicated that CaPp and CaPf maintained the characteristic peaks for this class of material. Additionally, the calcium assay study demonstrated a higher Ca uptake for CaPp compared to CaPf for up to 5 days. Furthermore, pH measurements revealed that the collagen coating prevented the acidification of the medium, leading to higher pH values for CaPp/Col and CaPf/Col. The histological analysis showed that CaPf/Col demonstrated a higher amount of newly formed bone in the region of the defect and a reduced presence of material. In summary, the results indicated that the fibrous CaP enriched with the organic part (collagen) glassy scaffold presented good degradability and bone-forming properties and also supported Runx2 and RANKL expression. These results show that the present CaP/Col fibrous composite may be used as a bone graft for inducing bone repair.

Temporal modifications in bone following spinal cord injury in rats.

Introduction The aim of this study was to investigate the temporal modifications in bone mass, bone biomechanical properties and bone morphology in spinal cord injured rats 2, 4 and 6 weeks after a transection. Material and methods Control animals were randomly distributed into four groups (n = 10 each group): control group (CG) – control animals sacrificed immediately after surgery; spinal cord-injured 2 weeks (2W) – spinal cord-injured animals sacrificed 2 weeks after surgery; spinal cord-injured 4 weeks (4W) – spinal cord-injured animals sacrificed 4 weeks after surgery; spinal cord-injured 6 weeks (6W) – spinal cord-injured animals sacrificed 6 weeks after surgery. Results Biomechanical properties of the right tibia were determined by a three-point bending test and injured animals showed a statistically significant decrease in maximal load compared to control animals. The right femur was used for densitometric analysis and bone mineral content of the animals sacrificed 4 and 6 weeks after surgery was significantly higher compared to the control animals and animals sacrificed 2 weeks after surgery. Histopathological and morphological analysis of tibiae revealed intense resorptive areas in the group 2 weeks after injury only. Conclusions The results of this study show that this rat model is a valuable tool to investigate bone remodeling processes specifically associated with SCI. Taken together, our results suggest that spinal cord injury induced bone loss within 2 weeks after injury in rats.

DNA damage, p53, Ki-67 and COX-2 expression in rat tongue cells exposed to nandrolone decanoate.

Abstract The objective of this article was to evaluate the impact potential of nandrolone decanoate on DNA damage, cellular regulatory proteins and cyclooxygenase (COX)-2 in oral mucosa cells of Wistar rats. A total of 40 rats were distributed into four groups. Two experimental groups were treated with nandrolone decanoate, at 5 mg/kg doses, subcutaneously, three times a week in two periods: 15 and 30 days. The remaining groups received only 0.9% saline subcutaneously, three times a week. To evaluate genetic damage, nandrolone decanoate at 15 mg/kg dose was exposed to 24 h. In the histopathological analysis, no remarkable morphological changes were observed in tongue tissue in all groups. Significant increase in immunoexpression of Ki-67, p53, COX-2 proteins was detected in the groups treated with nandrolone decanoate during 15 and 30 days, when compared to their respective controls. A positive correlation between immunoexpression of p53 and COX-2 protein was detected following nandrolone decanoate exposure. DNA damage was induced by nandrolone decanoate in oral mucosa cells at 15 mg/kg dose. Our results suggest that nandrolone decanoate was able to alter the expression of cell cycle-related proteins, as well as to induce genetic damage and COX-2 immunoexpression in tongue cells of Wistar rats.