RESUMO
This study aimed to develop bone regenerative therapeutic strategies, based on the addition of bone marrow stromal cells (BMSC) on bioglass/collagen (BG/COL) scaffolds. For this purpose, an in vivo study was conducted using tissue response of the BG/COL scaffolds combined with BMSC in a critical-size defects. Wistar rats were submitted to the surgical procedure to perform the cranial critical size bone defects and distributed in four groups (20 animals per group): Control Group (CG) (rats submitted to the cranial bone defect surgery without treatment), Bioglass Group (BG) (rats treated with BG), BG/COL Group (rats treated with BG/COL) and Bioglass/Collagen and BMSC Group (BG/COL/BMSC) (rats treated with BG/COL scaffolds enriched with BMSCs). Animals were euthanized 15 and 30 days after surgery. Scanning electron microscopy, histopathological and immunohistochemistry analysis were used. SEM analysis demonstrated that porous scaffolds were obtained, and Col fibers were successfully impregnated to BG matrices. The implantation of the BMSC on BG/COL based scaffolds was effective in stimulating newly bone formation and produced an increased immunoexpression of markers related to the bone repair. These results highlight the potential of BG/COL scaffolds and BMSCs to be used as a therapeutic approach for bone regeneration.
Assuntos
Células-Tronco Mesenquimais , Alicerces Teciduais , Ratos , Animais , Ratos Wistar , Colágeno/farmacologia , Osteogênese , Regeneração Óssea , Modelos Teóricos , Células da Medula Óssea , Engenharia Tecidual/métodosRESUMO
Biomaterial-based bone grafts have an important role in the field of bone tissue engineering. One of the most promising classes of biomaterials is collagen, including the ones from marine biodiversity (in general, called spongin (SPG)). Also, hydroxyapatite (HA) has an important role in stimulating bone metabolism. Therefore, this work investigated the association of HA and SPG composites in order to evaluate their physico-chemical and morphological characteristics and their in vitro biological performance. For this, pre-set composite disks were evaluated by means of mass loss after incubation, pH, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and "in vitro" cell viability. pH measurements showed no statistical difference between groups. Moreover, a higher mass loss was observed for HA/SPG70/30 compared to the other groups for all experimental periods. Moreover, SEM representative micrographs showed the degradation of the samples with and without immersion. FTIR analysis demonstrated the absorption peaks for poly(methyl methacrylate) (PMMA), HA, and SPG. A higher L292 cell viability for control and PMMA was observed compared to HA and HA/SPG 90/10. Also, HA/SPG 70/30 showed higher cell viability compared to HA and HA/SPG 90/10 on days 3 and 7 days of culture. Furthermore, HA showed a significant lower MC3T3 cell viability compared to control and HA/SPG 70/30 on day 3 and no significant difference was observed between the composites in the last experimental period. Based on our investigations, it can be concluded that the mentioned composites were successfully obtained, presenting improved biological properties, especially the one mimicking the composition of bone (with 70% of HA and 30% of SPG). Consequently, these data highlight the potential of the introduction of SPG into HA to improve the performance of the graft for bone regeneration applications. Further long-term studies should be carried out to provide additional information concerning the late stages of material degradation and bone healing in the presence of HA/SPG.
Assuntos
Materiais Biocompatíveis/química , Substitutos Ósseos/química , Colágeno/química , Durapatita/química , Polimetil Metacrilato/química , Alicerces Teciduais , Animais , Materiais Biocompatíveis/farmacologia , Substitutos Ósseos/farmacologia , Osso e Ossos/citologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Colágeno/farmacologia , Durapatita/farmacologia , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Camundongos , Células NIH 3T3 , Polimetil Metacrilato/farmacologia , Poríferos/química , Engenharia Tecidual/métodosRESUMO
The exhaustion of food resources which occurs during the ontogenetic growth of Ascia monuste orseis (Godart) results in the dispersion of older larvae to nearby plants in order to complete their development, which might expose these animals to the nutritional variation of the hosts found. This study aimed to verify whether the food ingested in the beginning of the development influences the larvae host preference and whether the shift to a new host can affect the digestion and performance of A. monuste orseis, using two natural hosts: kale (Brassica oleracea var. acephala) and rocket (Eruca sativa), or kale and cabbage (B. oleracea var. capitata). Larvae were reared throughout their larval development on a single host or on two different hosts. When a host change was tested, larvae were reared for four instars on a host, and offered the other host plant in the fifth instar. Development time, percentage of pupation and emergence, pupal weight, fecundity and digestive indices were evaluated. The change in feeding preference for kale and for rocket in the fourth instar, when those were the original hosts, respectively, shows that prior experience plays a major role in food preference of immature A. monuste orseis. The shift can be beneficial for larval development, depending on the order of the hosts; in general, larvae fed on kale at the end of the development showed better performance. Our results presented strong evidence of a considerable phenotypic plasticity in A. monuste orseis for host preferences.
Assuntos
Borboletas , Comportamento Alimentar , Preferências Alimentares , Animais , Brassicaceae , LarvaRESUMO
Os autores enfocam o caso de uma crianca acometida por peritonite primaria causada por Escherichia coli. Trata-se de uma afeccao rara, sendo este um agente etiologico incomum. Os autores dao enfase aos aspectos de diagnostico e terapeutica empregados no caso