Treatment of periodontal disease with an Er,Cr:YSGG laser in rats exposed to cigarette smoke inhalation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise histomorfométrica do reparo ósseo em tíbias de ratos castrados submetidos ao efeito do alendronato sódico

This study used histomorphometric analysis to investigate the effect of sodium alendronate, used for the treatment of osteoporosis, on the repair of surgically-induced bone defects in the tibia of castrated rats. Methods: The castrated animals were given subcutaneous injections of sodium alendronate (0.7mg/Kg) diluted in saline once a week; the control animals were given the same dose of saline. At 16, 30 and 44 days after the first injection of sodium alendronate, the animals were sacrificed and the right tibias were removed and processed for histomorphometric analysis. The volumetric bone mineral density was estimated by a reticular grid (25 points) attached to a light microscope. The number of points on the bone tissue was counted in the histological sections, totaling 100 points/animal. Results: The results revealed that sodium alendronate stimulated bone formation in castrated rats in all occasions, mainly at 16 and 30 days. Conclusion: Sodium alendronate affects mineral homeostasis, promoting bone repair.

Análise histomorfométrica da influência do Alendronato sódico no processo de reparo ósseo em tíbia de ratas submetidas a ovariectomia

The sodium alendronate (AS), considered as inhibitor in the osteoclasts- mediated bone resorption, promotes final effect of inhibition of resorption and increases bone mass. The objective of this research was to assess, by histomorphometry, the effect of sodium alendronate in repair bone of ovariectomized rats, in which there was performed a bone defect in the right tibia. The treated rats received a subcutaneous injection of sodic alendronate once a week, at 0.7 mg / kg, diluted with saline solution; the controls received the same volume of saline solution. In the periods of 16, 30 and 44 days after the first dose of AS, the animals were sacrificed, the right tibia was removed and processed for histomorphometric analysis. Four non-serial fields were used for the density volume quantification utilizing an integrative eyepiece with 25 points, totalizing 100 points per animal. Based on the results, the present study concludes that the ovariectomy induced osteoporosis and that the AS stimulated the bone formation. In addition, the ovariectomy decreased the estrogen levels. However, this procedure did not significantly influence the action of sodic alendronate.

Avaliação do uso de Selante de Fibrina derivado do veneno de serpente como arcabouço biológico de células tronco mesenquimais na regeneração óssea do fêmur de ratos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação do efeito osteoindutivo do PDGF-BB associado a diferentes carreadores na regeneração óssea em cavidades cirurgicamente criadas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da ovariectomia e da reposição hormonal no reimplante dentário imediato: análise histomorfométrica e imunoistoquímica em ratas

Pós-graduação em Odontologia - FOA

Fixação do enxerto ósseo autógeno em bloco com adesivos a base de cianoacrilato ou parafuso de titânio: estudo histológico em coelhos

Pós-graduação em Odontologia - FOA

Diabetes reduces mesenchymal stem cells in fracture healing through a TNF alpha-mediated mechanism

Diabetes interferes with bone formation and impairs fracture healing, an important complication in humans and animal models. The aim of this study was to examine the impact of diabetes on mesenchymal stem cells (MSCs) during fracture repair.Fracture of the long bones was induced in a streptozotocin-induced type 1 diabetic mouse model with or without insulin or a specific TNF alpha inhibitor, pegsunercept. MSCs were detected with cluster designation-271 (also known as p75 neurotrophin receptor) or stem cell antigen-1 (Sca-1) antibodies in areas of new endochondral bone formation in the calluses. MSC apoptosis was measured by TUNEL assay and proliferation was measured by Ki67 antibody. In vitro apoptosis and proliferation were examined in C3H10T1/2 and human-bone-marrow-derived MSCs following transfection with FOXO1 small interfering (si)RNA.Diabetes significantly increased TNF alpha levels and reduced MSC numbers in new bone area. MSC numbers were restored to normal levels with insulin or pegsunercept treatment. Inhibition of TNF alpha significantly reduced MSC loss by increasing MSC proliferation and decreasing MSC apoptosis in diabetic animals, but had no effect on MSCs in normoglycaemic animals. In vitro experiments established that TNF alpha alone was sufficient to induce apoptosis and inhibit proliferation of MSCs. Furthermore, silencing forkhead box protein O1 (FOXO1) prevented TNF alpha-induced MSC apoptosis and reduced proliferation by regulating apoptotic and cell cycle genes.Diabetes-enhanced TNF alpha significantly reduced MSC numbers in new bone areas during fracture healing. Mechanistically, diabetes-enhanced TNF alpha reduced MSC proliferation and increased MSC apoptosis. Reducing the activity of TNF alpha in vivo may help to preserve endogenous MSCs and maximise regenerative potential in diabetic patients.

Histomorphometric analysis of pure titanium implants with porous surface versus rough surface

The purpose of this study was to analyze the bone repair around commercially pure titanium implants with rough and porous surface, fabricated using powder metallurgy technique, after their insertion in tibiae of rabbits. Seven male rabbits were used. Each animal received 3 porous-surface implants in the left tibia and 3 rough-surface implants in the right tibia. The rabbits were sacrificed 4 weeks after surgery and fragments of the tibiae containing the implants were submitted to histological and histomorphometric analyses to evaluate new bone formation at the implant-bone interface. Means (%) of bone neoformation obtained in the histomorphometric analysis were compared by Student's t-test for paired samples at 5% significance level.. The results of the histological analysis showed that osseointegration occurred for both types of implants with similar quality of bone tissue. The histomorphometric analysis revealed means of new bone formation at implant-bone interface of 79.69 ± 1.00% and 65.05 ± 1.23% for the porous- and rough-surface implants, respectively. Statistically significant difference was observed between the two types of implants with respect to the amount new bone formation (p<0.05). In conclusion, the porous-surface implants contributed to the osseointegration because they provide a larger contact area at implant-bone interface.

Use of a new fibrin sealant and laser irradiation in the repair of skull defects in rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Clopidogrel enhances mesenchymal stem cell proliferation following periodontitis

Bone formation is dependent on the differentiation of osteoblasts from mesenchymal stem cells (MSCs). In addition to serving as progenitors, MSCs reduce inflammation and produce factors that stimulate tissue formation. Upon injury, MSCs migrate to the periodontium, where they contribute to regeneration. We examined the effect of clopidogrel and aspirin on MSCs following induction of periodontitis in rats by placement of ligatures. We showed that after the removal of ligatures, which induces resolution of periodontal inflammation, clopidogrel had a significant effect on reducing the inflammatory infiltrate. It also increased the number of osteoblasts and MSCs. Mechanistically, the latter was linked to increased proliferation of MSCs in vivo and in vitro. When given prior to inducing periodontitis, clopidogrel had little effect on MSC or osteoblasts numbers. Applying aspirin before or after induction of periodontitis did not have a significant effect on the parameters measured. These results suggest that clopidogrel may have a positive effect on MSCs in conditions where a reparative process has been initiated.

Evaluation of crystallized biosilicate in the reconstruction of calvarial defects

The objective of this study was to assess the bone repair process of crystallized Biosilicate in surgically created defects on rats' calvaria. This biomaterial was recently developed for odontological use. We used fifteen rats (rattus norvegicus albinus, Wistar), and two 5 mm surgical defects were performed on each of them; the defects were made with trephine drill on the calvarium region prior to the biomaterial placement. Groups were divided as follows: Group 1-defect filled with clot; Group 2-defect filled with crystallized Biosilicate. After 7, 14 and 28 days the animals were killed, the parts were retrieved and slides were prepared for histological studies. Bone formation was satisfactory in all groups, with direct contact between biomaterial surface and bone and absence of infection signs. The 28 days periods showed better results, and statistically significant difference between Clot Group (90.2 %) and Biosilicate (58 %; p = 0.002) was seen, regarding presence of bone tissue on the surgical defects. Our study revealed that defects filled with clot present better results on bone formation compared to crystallized Biosilicate, which is considered a biocompatible material with favorable osteoconductive properties.

Avaliação comparativa do processo de incorporação de bloco sintético bifásico, e do osso autógeno: estudo histológico, histométrico e imunoistoquímico em coelhos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da inalação da fumaça de cigarro no reparo de enxertos ósseos autógenos onlay em ratas ovarectomizadas: estudo histomorfométrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Regeneração óssea guiada com o uso de membrana de copolímero PLA/PGA em levantamento da membrana do seio maxilar: estudo experimental com análises histomorfométrica e imunoistoquímica

Pós-graduação em Odontologia - FOA