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.

Nandrolone decanoate induces genetic damage in multiple organs of rats.

To evaluate the impact potential of nandrolone decanoate on DNA damage in multiple organs of Wistar rats by means of single-cell gel (comet) assay and micronucleus test. A total of 15 animals were distributed into three groups of five animals each as follows: control group = animal not exposed to nandrolone decanoate; experimental group = animals exposed to nandrolone decanoate for 24 h at 5 mg/kg subcutaneously; and experimental group = animals exposed to nandrolone decanoate for 24 h at 15 mg/kg subcutaneously. Significant statistical differences (p < 0.05) were noted in peripheral blood, liver, and heart cells exposed to nandrolone decanoate at the two doses evaluated. A clear dose-response relationship was observed between groups. Kidney cells showed genetic damage at only the highest dose (15 mg/kg) used. However, micronucleus data did not show remarkable differences among groups. In conclusion, the present study indicates that nandrolone decanoate induces genetic damage in rat blood, liver, heart, and kidney cells as shown by single-cell gel (comet) assay results.

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

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.

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 / 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

OBJETIVO: Verificar os efeitos da associação do Biosilicato® com o US e com o LLLT no processo de consolidação óssea em ratos, a partir da análise biomecânica e histológica. MÉTODOS: Foram utilizados 40 ratos machos distribuídos em quatro grupos (n = 10): grupo controle fratura sem tratamento (GCF); grupo tratado com Biosilicato® (GB); grupo tratado com Biosilicato® + laser (GBL); grupo tratado com Biosilicato® + US (GBUS). RESULTADOS: A análise biomecânica não apresentou diferença estatisticamente significativa nos grupos após o período experimental de 14 dias. Na análise morfométrica, o grupo controle apresentou presença moderada de tecido ósseo neoformado no interior dos defeitos e o grupo tratado com Biosilicato® apresentou resultados semelhantes. No entanto, foi observado o potencial osteogênico do biomaterial, uma vez que houve grande presença de células e tecido ósseo ao redor das partículas. Interessantemente, os grupos Biosilicato® associado ao laser terapêutico e ao US demonstraram quantidades menores de deposição de tecido ósseo quando comparados aos grupos controle fratura e Biosilicato®. CONCLUSÃO: A partir dos dados deste estudo podemos concluir que o Biosilicato® foi capaz de acelerar e potencializar a recuperação óssea, através da modulação do processo inflamatório e da estimulação da formação de tecido ósseo novo. No entanto, quando a LLLT ou o US foram associados, não foram encontrados resultados positivos.

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.

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.

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.