RESUMO
Lesions with bone loss may require autologous grafts, which are considered the gold standard; however, natural or synthetic biomaterials are alternatives that can be used in clinical situations that require support for bone neoformation. Collagen and hydroxyapatite have been used for bone repair based on the concept of biomimetics, which can be combined with chitosan, forming a scaffold for cell adhesion and growth. However, osteoporosis caused by gonadal hormone deficiency can thus compromise the expected results of the osseointegration of scaffolds. The aim of this study was to investigate the osteoregenerative capacity of collagen (Co)/chitosan (Ch)/hydroxyapatite (Ha) scaffolds in rats with hormone deficiency caused by experimental bilateral ovariectomy. Forty-two rats were divided into non-ovariectomized (NO) and ovariectomized (O) groups, divided into three subgroups: control (empty defect) and two subgroups receiving collagen/chitosan/hydroxyapatite scaffolds prepared using different methods of hydroxyapatite incorporation, in situ (CoChHa1) and ex situ (CoChHa2). The defect areas were submitted to macroscopic, radiological, and histomorphometric analysis. No inflammatory processes were found in the tibial defect area that would indicate immune rejection of the scaffolds, thus confirming the biocompatibility of the biomaterials. Bone formation starting from the margins of the bone defect were observed in all rats, with a greater volume in the NO groups, particularly the group receiving CoChHa2. Less bone formation was found in the O subgroups when compared to the NO. In conclusion, collagen/chitosan/hydroxyapatite scaffolds stimulate bone growth in vivo but abnormal conditions of bone fragility caused by gonadal hormone deficiency may have delayed the bone repair process.
Assuntos
Quitosana , Durapatita , Feminino , Ratos , Animais , Regeneração Óssea , Materiais Biocompatíveis , Colágeno , Alicerces TeciduaisRESUMO
The sebaceous gland (SG) is involved in different inflammatory, infectious and neoplastic processes of the skin and can be related to specific diseases, e.g., diabetes mellitus. Sometimes, the histological diagnosis requires complementary tests due to the ability of diseases to mimic other tumors. We evaluated the sebaceous gland density in Non-obese diabetic mice to analyze the N-acetylcystein effects and swimming exercise treatment in sebaceous glands healing, using specific staining in histochemistry and immunohistochemistry reactions in the identification of the lipid expression in the sebaceous gland. We investigated the intracytoplasmic lipid expression and analysis of gland density from SG in dorsal skin samples from the Non-obese diabetic (NOD mice) and diabetic animals submitted to antioxidant treatment and physical exercise. For histological analysis of the sebaceous glands, specific staining in histochemistry with sudan black and immunohistochemistry reaction with adipophilin were used in the evaluation. Statistical analysis showed significant proximity between the values of the control group and the diabetic group submitted to the swimming exercise (DS group) and similar values between the untreated diabetic group (UD group) and diabetic group treated with the antioxidant N-acetylcysteine (DNa group), which did not prevent possible differences where p < 0.01. Adipophilin (ADPH) immunohistochemistry permitted more intense lipid staining in SGs, the preservation of the SG in the control group, and a morphological deformed appearance in the UD and DNa groups. However, weak morphological recovery of the SG was observed in the DS-Na group, being more expressive in the DS group. In conclusion, the groups submitted to physical exercises showed better results in the recovery of the analyzed tissue, even being in the physiological conditions caused by spontaneous diabetes.
Assuntos
Acetilcisteína/farmacologia , Diabetes Mellitus Tipo 1/metabolismo , Lipídeos/biossíntese , Glândulas Sebáceas/efeitos dos fármacos , Natação/fisiologia , Animais , Antioxidantes/farmacologia , Glicemia/metabolismo , Diabetes Mellitus Tipo 1/sangue , Feminino , Humanos , Imuno-Histoquímica , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD , Perilipina-2/metabolismo , Glândulas Sebáceas/anatomia & histologia , Glândulas Sebáceas/metabolismo , Pele/efeitos dos fármacos , Pele/metabolismoRESUMO
Polymeric biomaterials composed of extracellular matrix components possess osteoconductive capacity that is essential for bone healing. The presence of collagen and the ability to undergo physicochemical modifications render these materials a suitable alternative in bone regenerative therapies. The objective of this study was to evaluate the osteogenic capacity of collagen-based matrices (native and anionic after alkaline hydrolysis) made from bovine intestinal serosa (MBIS). Twenty-five animals underwent surgery to create a cranial defect to be filled with native and anionic collagen matrixes, mmineralized and non mineralized. The animals were killed painlessly 6 weeks after surgery and samples of the wound area were submitted to routine histology and morphometric analysis. In the surgical area there was new bone formation projecting from the margins to the center of the defect. More marked bone neoformation occurred in the anionic matrices groups in such a way that permitted union of the opposite margins of the bone defect. The newly formed bone matrix exhibited good optical density of type I collagen fibers. Immunoexpression of osteocalcin by osteocytes was observed in the newly formed bone. Morphometric analysis showed a greater bone volume in the groups receiving the anionic matrices compared to the native membranes. Mineralization of the biomaterial did not increase its osteoregenerative capacity. In conclusion, the anionic matrix exhibits osteoregenerative capacity and is suitable for bone reconstruction therapies.
Assuntos
Regeneração Óssea/efeitos dos fármacos , Colágeno/farmacologia , Matriz Extracelular/transplante , Intestinos/química , Membrana Serosa/química , Fraturas Cranianas/tratamento farmacológico , Animais , Biomarcadores/metabolismo , Regeneração Óssea/fisiologia , Calcificação Fisiológica/fisiologia , Bovinos , Colágeno/química , Colágeno/isolamento & purificação , Expressão Gênica , Osteocalcina/genética , Osteocalcina/metabolismo , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Ratos , Ratos Wistar , Crânio/efeitos dos fármacos , Crânio/lesões , Crânio/patologia , Fraturas Cranianas/patologia , Cicatrização/efeitos dos fármacosRESUMO
Introdução: Os anticoncepcionais orais vêm sofrendo alterações em suas concentrações de estrogênio e progestogênio, baseando-se no fato de que doses mais baixas estão associadas a menor incidência de alterações metabólicas e de efeitos adversos, como o comprometimento da morfologia e função da artéria aorta. O objetivo deste estudo é avaliar a influência dos anticoncepcionais nas propriedades morfofuncionais da artéria aorta, através do método histoquímico, demonstrando sua utilidade nas análises histopatológicas. Métodos: Para tanto, foram utilizadas 15 ratas divididas em 3 grupos; Grupo controle (GC), cujos animais não receberam tratamento hormonal; Grupo 2 (G2), onde os animais receberam tratamento diário de 15 µg de etinilestradiol + 60 µg de gestodeno; e Grupo 3 (G3), que recebeu 30 µg de etinilestradiol + 75 µg de gestodeno. Após o tratamento, os animais foram eutanasiados e as artérias retiradas para análise histológica. Resultados: Os valores encontrados com a técnica de coloração histológica de hematoxilina e eosina (HE), bem como na coloração específica em histoquímica com Alcian Blue, demonstram que no G3, tratados com uma dosagem superior de hormônio, 8% das ratas tem aumento relevante da espessura de suas artérias, ou seja, superior ao G2, que recebeu dosagem menor de hormônio, e GC, o qual não recebeu nenhum tipo de tratamento. Conclusão: Este estudo demonstra que existem relações entre o espessamento das artérias, de ratas submetidas a dosagens de etinilestradiol e gestodeno, com a grande quantidade de mucopolissacarídeos depositados entre as túnicas das artérias. (AU)
Introduction: Pharmacological development of hormonal contraceptives has been undergoing changes in estrogen and progesterone doses, based on the fact that lower doses are associated with a lower incidence of metabolic changes and adverse effects, such as impairment of morphology and function of the aortic artery. The aim of this study is to evaluate the influence of contraceptives on the morphofunctional properties of the aortic artery, using the histochemical method, demonstrating its usefulness in histopathological analyzes. Methods: For this purpose, 15 rats were divided into 3 groups; Control group (GC), whose animals did not receive hormonal treatment; Group 2 (G2), where the animals received a daily treatment of 15 µg of ethinylestradiol + 60 µg of gestodene; and Group 3 (G3), whose animals received 30 µg of ethinylestradiol + 75 µg of gestodene. After treatment, the animals were sacrificed and the arteries removed for histologic analysis. Results: The values found, with HE measurements and Alcian Blue histochemical staining, showed that in G3, treated with a higher hormone dosage, there are 8% of the rats with a relevant increase in the thickness of their arteries, that is, higher than that of G2, which received lower dosage of hormone and that of GC, which received no treatment. Conclusion: This study demonstrates that there are relations between the thickening of the arteries of rats submitted to dosages of ethinylestradiol and gestodene with the great amount of mucopolysaccharides deposited between the tunics of the arteries. (AU)
Assuntos
Animais , Feminino , Ratos , Aorta/efeitos dos fármacos , Aorta/fisiopatologia , Etinilestradiol/efeitos adversos , Etinilestradiol/farmacologia , Ratos , Anticoncepcionais Orais/efeitos adversos , Modelos Animais de DoençasRESUMO
Bone metabolism is influenced by different factors and muscle activity acts as a stimulator of bone plasticity. Conditions such as nerve injuries can compromise bone physiology due to muscle inactivity. Preview studies have shown that nerve damage reduces P substance and calcitonin gene-related peptides, also known as neuropeptides that may have a key role on bone healing. Therefore, this study evaluated the osseointegration of hydroxyapatite implants in tibial defects of rats submitted to unilateral sciatic nerve section. Twelve Wistar rats were divided into two groups (G1 and G2). In G1, the sciatic nerve was left intact and in G2 the left sciatic nerve was completely sectioned. An experimental tibial bone defect was then created in both groups and filled with hydroxyapatite granules. The animals were sacrificed 2 months after implantation and samples were submitted to macroscopic inspection and histological analysis. Good radiopacity of the hydroxyapatite granules and radiographic definition of the bone defect were noted. Histologic analysis revealed formation of new bone adjacent to the hydroxyapatite granules in G1 and, to a lesser extent, in G2 in which the proliferation of connective tissue predominated at the implant site. The formation of new bone stimulated by hydroxyapatite in bone defects can be expected even in animals with limb paralysis due to nerve injury; however, bone formation occurs at a slower speed in these animals and the volume of newly formed bone is lower.
El metabolismo óseo está influenciado por diferentes factores y la actividad muscular como un estimulador de la plasticidad ósea. Condiciones tales como lesiones nerviosas pueden comprometer la fisiología ósea debido a la inactividad muscular. Estudios previos han demostrado que el daño nervioso reduce la sustancia P y el péptido relacionado con el gen de la calcitonina, también conocidos como neuropéptidos que pueden tener un papel clave en la cicatrización ósea. Este estudio evaluó la oseointegración de los implantes de hidroxiapatita en defectos tibiales de ratas sometidas a la sección del nervio ciático unilateralmente. Doce ratas Wistar se dividieron en dos grupos (G1 y G2). En G1, el nervio ciático se dejó intacto y en el G2 el nervio ciático izquierdo fue completamente seccionado. Un defecto óseo tibial fue creado experimentalmente en ambos grupos y se rellenó con gránulos de hidroxiapatita. Los animales se sacrificaron 2 meses después de la implantación y las muestras fueron sometidas a inspección macroscópica y el análisis histológico. Se observó buena radiopacidad de los gránulos de hidroxiapatita y definición radiográfica del defecto óseo. El análisis histológico reveló neoformación ósea adyacente a los gránulos de hidroxiapatita en G1 y, en menor medida en G2, donde la proliferación de tejido conectivo predominó en el sitio de implante. La neoformación ósea estimulada por hidroxiapatita en defectos óseos se puede esperar incluso en animales con parálisis de los miembros producto de una lesión nerviosa; sin embargo, la formación de hueso se produce a menor velocidad en estos animales y su volumen es menor.
Assuntos
Animais , Masculino , Ratos , Durapatita/química , Osseointegração/fisiologia , Próteses e Implantes , Nervo Isquiático/cirurgia , Tíbia/cirurgia , Ratos Wistar , Nervo Isquiático/lesões , Tíbia/patologiaRESUMO
Tissue engineering has special interest in bone tissue aiming at future medical applications Studies have focused on recombinant human bone morphogenetic protein-2 (rhBMP-2) and natural latex proteins due to the osteogenic properties of rhBMP-2 and the angiogenic characteristic of fraction 1 protein (P-1) extracted from the rubber tree Hevea brasiliensis. Furthermore, heterologous fibrin sealant (FS) has been shown as a promising alternative in regenerative therapies. The aim of this study was to evaluate these substances for the repair of bone defects in rats. A bone defect measuring 3mm in diameter was created in the proximal metaphysis of the left tibia of 60 rats and was implanted with rhBMP-2 or P-1 in combination with a new heterologous FS derived from snake venom. The animals were divided into six groups: control (unfilled bone defect), rhBMP-2 (defect filled with 5µg rhBMP-2), P-1 (defect filled with 5µg P-1), FS (defect filled with 8µg FS), FS/rhBMP-2 (defect filled with 8µg FS and 5µg rhBMP-2), FS/P-1 (defect filled with 8µg FS and 5µg P-1). The animals were sacrificed 2 and 6 weeks after surgery. The newly formed bone projected from the margins of the original bone and exhibited trabecular morphology and a disorganized arrangement of osteocyte lacunae. Immunohistochemical analysis showed intense expression of osteocalcin in all groups. Histometric analysis revealed a significant difference in all groups after 2 weeks (p<0.05), except for the rhBMP-2 and FS/rhBMP-2 groups (p>0.05). A statistically significant difference (p<0.05) was observed in all groups after 6 weeks in relation to the volume of newly formed bone in the surgical area. In conclusion, the new heterologous fibrin sealant was found to be biocompatible and the combination with rhBMP-2 showed the highest osteogenic and osteoconductive capacity for bone healing. These findings suggest a promising application of this combination in the regeneration surgery.
Assuntos
Proteína Morfogenética Óssea 2/uso terapêutico , Substitutos Ósseos/uso terapêutico , Fibrina/uso terapêutico , Proteínas de Plantas/uso terapêutico , Animais , Regeneração Óssea , Feminino , Humanos , Látex/química , Ratos Wistar , Tíbia/patologia , Tíbia/fisiopatologia , Engenharia TecidualRESUMO
This study evaluated the osteogenic capacity of a new fibrin sealant (FS) combined with bone graft and laser irradiation in the bone repair. Defects were created in the skull of 30 rats and filled with autogenous graft and FS derived from snake venom. Immediately after implantation, low-power laser was applied on the surgical site. The animals were divided in: control group with autogenous graft (G1), autogenous graft and laser 5 J/cm2 (G2), autogenous graft and laser 7 J/cm2 (G3), autogenous graft and FS (G4), autogenous graft, FS and laser 5 J/cm2 (G5), autogenous graft, FS and laser 7 J/cm2 (G6). The animals were sacrificed 6 weeks after implant. Results showed absence of inflammatory infiltrate in the bone defect. New bone formation occurred in all groups, but it was most intense in G6. Thus, the FS and laser 7 J/cm2 showed osteoconductive capacity and can be an interesting resource to be applied in surgery of bone reconstruction.
Este estudo avaliou a capacidade osteogênica de um novo selante de fibrina (FS) associado com enxerto ósseo e irradiação laser no reparo ósseo. Defeitos foram criados no crânio de 30 ratos e preenchidos com enxerto autógeno e FS derivado do veneno de cobra. Imediatamente após implantação, foi aplicado laser de baixa potência na área cirúrgica. Os animais foram divididos em grupo controle com autógeno (G1), autógeno e laser 5 J/cm2 (G2), autógeno e laser 7J/cm2 (G3), autógeno e FS (G4), autógeno, FS e laser 5J/cm2 (G5), autógeno, FS e laser 7J/cm2 (G6). Os animais foram sacrificados 6 semanas após implante. Resultados mostraram ausência de infiltrado inflamatório no defeito ósseo. Neoformação óssea ocorreu em todos os grupos, entretanto, foi mais intenso em G6. Desta maneira, o FS e laser 7J/cm2 mostraram capacidade osteocondutiva e podem ser um interessante recurso a ser aplicado nas cirurgias de reconstrução óssea.
Assuntos
Animais , Masculino , Ratos , Adesivo Tecidual de Fibrina/farmacologia , Crânio/efeitos da radiação , Desenvolvimento Ósseo/efeitos dos fármacos , Desenvolvimento Ósseo/efeitos da radiação , Lasers , Ratos Wistar , Crânio/efeitos dos fármacosRESUMO
This study evaluated the osteogenic capacity of a new fibrin sealant (FS) combined with bone graft and laser irradiation in the bone repair. Defects were created in the skull of 30 rats and filled with autogenous graft and FS derived from snake venom. Immediately after implantation, low-power laser was applied on the surgical site. The animals were divided in: control group with autogenous graft (G1), autogenous graft and laser 5 J/cm2 (G2), autogenous graft and laser 7 J/cm2 (G3), autogenous graft and FS (G4), autogenous graft, FS and laser 5 J/cm2 (G5), autogenous graft, FS and laser 7 J/cm2 (G6). The animals were sacrificed 6 weeks after implant. Results showed absence of inflammatory infiltrate in the bone defect. New bone formation occurred in all groups, but it was most intense in G6. Thus, the FS and laser 7 J/cm2 showed osteoconductive capacity and can be an interesting resource to be applied in surgery of bone reconstruction.