RESUMO
Composites of biodegradable polymers and calcium phosphate are bioactive and flexible, and have been proposed for use in tissue engineering and bone regeneration. When associated with the broad-spectrum antibiotic doxycycline (DOX), they could favor antimicrobial action and enhance the action of osteogenic composites. Composites of polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and a bioceramic of biphasic calcium phosphate Osteosynt® (BCP) were loaded with DOX encapsulated in ß-cyclodextrin (ßCD) and were evaluated for effects on osteoblastic cell cultures. The DOX/ßCD composite was prepared with a double mixing method. Osteoblast viability was assessed with methyl tetrazolium (MTT) assays after 1day, 7day, and 14days of composite exposure; alkaline phosphatase (AP) activity and collagen production were evaluated after 7days and 14days, and mineral nodule formation after 14days. Composite structures were evaluated by scanning electron microscopy (SEM). Osteoblasts exposed to the composite containing 25µg/mL DOX/ßCD had increased cell proliferation (p<0.05) compared to control osteoblast cultures at all experimental time points, reaching a maximum in the second week. AP activity and collagen secretion levels were also elevated in osteoblasts exposed to the DOX/ßCD composite (p<0.05 vs. controls) and reached a maximum after 14days. These results were corroborated by Von Kossa test results, which showed strong formation of mineralization nodules during the same time period. SEM of the composite material revealed a surface topography with pore sizes suitable for growing osteoblasts. Together, these results suggest that osteoblasts are viable, proliferative, and osteogenic in the presence of a DOX/ßCD-containing BCP ceramic composite.
Assuntos
Fosfatos de Cálcio , Ciclodextrinas , Doxiciclina , Portadores de Fármacos , Ácido Láctico , Osteoblastos/metabolismo , Osteogênese/efeitos dos fármacos , Poliésteres , Ácido Poliglicólico , Animais , Fosfatos de Cálcio/química , Fosfatos de Cálcio/farmacocinética , Fosfatos de Cálcio/farmacologia , Células Cultivadas , Ciclodextrinas/química , Ciclodextrinas/farmacocinética , Ciclodextrinas/farmacologia , Doxiciclina/química , Doxiciclina/farmacocinética , Doxiciclina/farmacologia , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Portadores de Fármacos/farmacologia , Ácido Láctico/química , Ácido Láctico/farmacocinética , Ácido Láctico/farmacologia , Masculino , Osteoblastos/citologia , Poliésteres/química , Poliésteres/farmacocinética , Poliésteres/farmacologia , Ácido Poliglicólico/química , Ácido Poliglicólico/farmacocinética , Ácido Poliglicólico/farmacologia , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Ratos , Ratos WistarRESUMO
OBJECTIVE: The aim of this study was to produce dense granules of tricalcium phosphate (ß-TCP) and magnesium (Mg) substituted ß-TCP, also known as ß-TCMP (Mg/Ca=0.15 mol), in order to evaluate the impact of Mg incorporation on the physicochemical parameters and in vitro biocompatibility of this novel material. MATERIAL AND METHODS: The materials were characterized using X-ray diffraction (XRD), infrared spectroscopy (FTIR), electron microscopy and inductively coupled plasma (ICP). Biocompatibility was assayed according to ISO 10993-12:2007 and 7405:2008, by two different tests of cell survival and integrity (XTT and CVDE). RESULTS: The XRD profile presented the main peaks of ß-TCP (JCPDS 090169) and ß-TCMP (JCPDS 130404). The characteristic absorption bands of TCP were also identified by FTIR. The ICP results of ß-TCMP granules extract showed a precipitation of calcium and release of Mg into the culture medium. Regarding the cytotoxicity assays, ß-TCMP dense granules did not significantly affect the mitochondrial activity and relative cell density in relation to ß-TCP dense granules, despite the release of Mg from granules into the cell culture medium. CONCLUSION: ß-TCMP granules were successfully produced and were able to release Mg into media without cytotoxicity, indicating the suitability of this promising material for further biological studies on its adequacy for bone therapy.
Assuntos
Materiais Biocompatíveis/toxicidade , Fosfatos de Cálcio/toxicidade , Magnésio/toxicidade , Análise de Variância , Materiais Biocompatíveis/farmacocinética , Substitutos Ósseos/farmacocinética , Substitutos Ósseos/toxicidade , Fosfatos de Cálcio/farmacocinética , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas/efeitos dos fármacos , Magnésio/farmacocinética , Teste de Materiais , Microscopia Eletrônica de Varredura , Osteoblastos/efeitos dos fármacos , Análise Espectral , Fatores de Tempo , Testes de Toxicidade , Difração de Raios XRESUMO
Objective: The aim of this study was to produce dense granules of tricalcium phosphate (β-TCP) and magnesium (Mg) substituted β-TCP, also known as β-TCMP (Mg/Ca=0.15 mol), in order to evaluate the impact of Mg incorporation on the physicochemical parameters and in vitro biocompatibility of this novel material. Material and Methods: The materials were characterized using X-ray diffraction (XRD), infrared spectroscopy (FTIR), electron microscopy and inductively coupled plasma (ICP). Biocompatibility was assayed according to ISO 10993-12:2007 and 7405:2008, by two different tests of cell survival and integrity (XTT and CVDE). Results: The XRD profile presented the main peaks of β-TCP (JCPDS 090169) and β-TCMP (JCPDS 130404). The characteristic absorption bands of TCP were also identified by FTIR. The ICP results of β-TCMP granules extract showed a precipitation of calcium and release of Mg into the culture medium. Regarding the cytotoxicity assays, β-TCMP dense granules did not significantly affect the mitochondrial activity and relative cell density in relation to β-TCP dense granules, despite the release of Mg from granules into the cell culture medium. Conclusion: β-TCMP granules were successfully produced and were able to release Mg into media without cytotoxicity, indicating the suitability of this promising material for further biological studies on its adequacy for bone therapy.
Assuntos
Materiais Biocompatíveis/toxicidade , Fosfatos de Cálcio/toxicidade , Magnésio/toxicidade , Análise de Variância , Materiais Biocompatíveis/farmacocinética , Substitutos Ósseos/farmacocinética , Substitutos Ósseos/toxicidade , Fosfatos de Cálcio/farmacocinética , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas/efeitos dos fármacos , Teste de Materiais , Microscopia Eletrônica de Varredura , Magnésio/farmacocinética , Osteoblastos/efeitos dos fármacos , Análise Espectral , Fatores de Tempo , Testes de Toxicidade , Difração de Raios XRESUMO
One thousand male Hubbard chicks were used in a 21-d study (10 birds per battery cage) to determine relative biological availability of phosphorus in seven samples of commercial dicalcium phosphate, expected to contain variable amounts of monocalcium phosphate. Five samples were from established producers in Brazil and two from the U.S. Pure calcium phosphate dibasic dihydrate was used as the reference standard. Phosphates were added to the corn-soybean basal diet (22.5% CP; 0.4% total phosphorus) to provide 0.1, 0.2, and 0.3% supplemental phosphorus. The calcium level was 1.0% for all diets. Left tibias were removed for bone ash (BA) and bone strength (BS) determination. Body weight, feed intake (FI), BA, BS, and plasma phosphorus increased (P < 0.01) and plasma calcium and alkaline phosphatase decreased (P < 0.01) with increasing dietary phosphorus regardless of source. The availability of phosphorus for each test phosphate was determined by slope ratio, with BW, BA, and BS regressed on phosphorus added within each phosphorus source. A relative biological value (RBV) was calculated based on BW, BA, and gain:feed ratio. Availability based on BW ranged from 97.07 to 110.41%. When BA was the criterion, values were 80.32 to 107.84% and for BS were 79.34 to 110.52%. The RBV ranged from 97.55 to 100.60%. Phosphate sources did not vary greatly in phosphorus availability. Overall phosphorus availability averages were higher for BW (103%) and RBV (99%) and lowest for BA (96%) and BS (94%).