Resposta biológica à implantação subcutânea de nanopartículas de hidroxiapatite em ratos diabéticos
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2015-04-23
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Patologias do tecido ósseo, originárias de várias causas, nomeadamente traumas, infeções ou doenças ósseas, são muito comuns na nossa sociedade. Na situação de diabetes mellitus, estes defeitos ósseo estão agravados e o seu tratamento apresenta uma maior dificuldade para os clínicos. Nos últimos anos a nanotecnologia tem fornecido variadíssimos benefícios no campo da engenharia do tecido ósseo, no entanto nenhuma das soluções tem resolvido totalmente os diversos desafios que pressupõem a reparação óssea. Desta forma, têm sido estudadas novas soluções terapêuticas para resolver este problema, e o desenvolvimento de novos biomateriais fabricados com nanopartículas que simulem a estrutura e composição do osso, favorecendo a sua regeneração, têm sido equacionados. Assim este trabalho tem como principal objetivo o estudo da biocompatibilidade de uma preparação de nanopartículas de hidroxiapatite (NanoXIM•HAp102®) na condição de diabetes, usando para tal um modelo de implante subcutâneo em ratos Wistar.
Neste estudo foram usados 16 ratos machos da estirpe Wistar, dos quais 10 foram submetidos à indução da diabetes, por via intraperitonial, com uma única administração de 55 mg/Kg de estreptozotocina (STZ), sendo os restantes injetados com soro tampão citrato (grupo controlo). Duas semanas após a indução da diabetes, implantou-se subcutaneamente em todos os animais 0,5 ml de suspensão de nanopartículas de hidroxiapatite (nano-HAp). Os animais foram sacrificados às 48h e 3 semanas, sendo recolhido o sangue, órgãos, e tecido subcutâneo com a nano-HAp, para avaliar a atividade e expressão de variados marcadores séricos, assim como proceder à análise histopatológica.
Os animais diabéticos apresentaram uma diminuição do peso corporal e um aumento do peso relativo dos rins e do fígado quando comparado com os respetivos grupos controlo. Os valores dos marcadores de função renal, ureia e creatinina, e das enzimas hepáticas ALT e FA, encontraram-se elevados nos animais diabéticos comparativamente com os controlos. Às 48h, verificou-se a existência de uma resposta inflamatória aguda, com presença de neutrófilos e linfócitos, e uma resposta inflamatória crónica caracterizada pela presença de macrófagos e células gigantes, às 3 semanas. Tanto a resposta inflamatória, como a reabsorção das nanopartículas encontraram-se diminuídas nos grupos diabéticos comparativamente com o respetivo grupo controlo. Constatou-se a presença de uma cápsula fibrosa nos grupos experimentais das 3 semanas, sendo que esta foi menor no grupo diabético comparativamente com o respetivo grupo controlo. Observou-se ainda alguma agregação de
nano-HAp, tendo esta sido mais intensa em ambos os grupos diabéticos, e dentro destes maior às 3 semanas.
Uma vez que não se verificou uma reação exacerbada e que ocorreu reabsorção do biomaterial, sem sinal de toxicidade hepática ou renal, na quantidade testada, podemos concluir que as nano-HAp não apresentam toxicidade. Embora se tenha observado reabsorção das nano-HAp ao longo do período experimental, constatou-se que este processo era bastante mais lento nas condições diabéticas.
Pathologies of bone tissue, that are provided from different causes, including trauma, infections or bone diseases, are very common in our society. In the specific case of diabetes mellitus, the bone defects are intensified and its treatment presents a major difficulty for clinicians. Actually, nanotechnology provides many different benefits in the field of bone tissue engineering, however, any solutions have completely solved the challenges that require bone repair. In this way, it has been studied new therapeutic solutions to solve this problem, the development of new biomaterials made from nanoparticles that acquire a similar structure and composition of the original bone, promoting regeneration, have been solved. The main objective of this work is the study of the biocompatibility, of hydroxyapatite nanoparticles (NanoXIM • HAp102 ®) in diabetic conditions, using for such a model of subcutaneous implantation in Wistar rats. This study used 16 male rats of the Wistar strain, 10 of which were subjected to induction of diabetes with single intraperitoneally administration of 55 mg / kg streptozotocin (STZ), and the remaining were injected with physiological serum (the control group). After the induction of diabetes, was subcutaneously implanted 0,5 ml hydroxyapatite nanoparticles (nano-HAp). The animals were sacrificed at 48 hours and 3 weeks, being collected the blood, organs, and subcutaneous tissue, with nano-Hap, to evaluate the expression and the activity of various serum markers, as well as the histopathology. Diabetic animals showed a decrease in body weight and an increase in the relative weight of the liver and kidneys when compared with the respective control groups. The values of markers of renal function, urea and creatinine, and liver enzymes ALT and FA, were also higher in diabetic animals compared with control. At 48 h, it was found a several inflammatory response with neutrophils and lymphocytes, and a chronic inflammatory response characterized by the presence of macrophages and giant cells, at 3 weeks. The inflammatory response and the reabsorption of the nanoparticles were found decreased in diabetic group compared with the respective control group. It was observed the presence of a fibrous capsule in the experimental groups of the 3 weeks, but it was lower in the diabetic group as compared to the respective control group. There was also some aggregation of nano-Hap, that was more intense in both diabetic groups, and within these higher at 3 weeks. With the quantity tested, there has not been observed an overreaction and the biomaterial reabsorption occurred without signs of hepatic or renal toxicity. Although we observed a progressive reabsorption of nano-HAp throughout the experimental period, this process was significantly slower in diabetic conditions.
Pathologies of bone tissue, that are provided from different causes, including trauma, infections or bone diseases, are very common in our society. In the specific case of diabetes mellitus, the bone defects are intensified and its treatment presents a major difficulty for clinicians. Actually, nanotechnology provides many different benefits in the field of bone tissue engineering, however, any solutions have completely solved the challenges that require bone repair. In this way, it has been studied new therapeutic solutions to solve this problem, the development of new biomaterials made from nanoparticles that acquire a similar structure and composition of the original bone, promoting regeneration, have been solved. The main objective of this work is the study of the biocompatibility, of hydroxyapatite nanoparticles (NanoXIM • HAp102 ®) in diabetic conditions, using for such a model of subcutaneous implantation in Wistar rats. This study used 16 male rats of the Wistar strain, 10 of which were subjected to induction of diabetes with single intraperitoneally administration of 55 mg / kg streptozotocin (STZ), and the remaining were injected with physiological serum (the control group). After the induction of diabetes, was subcutaneously implanted 0,5 ml hydroxyapatite nanoparticles (nano-HAp). The animals were sacrificed at 48 hours and 3 weeks, being collected the blood, organs, and subcutaneous tissue, with nano-Hap, to evaluate the expression and the activity of various serum markers, as well as the histopathology. Diabetic animals showed a decrease in body weight and an increase in the relative weight of the liver and kidneys when compared with the respective control groups. The values of markers of renal function, urea and creatinine, and liver enzymes ALT and FA, were also higher in diabetic animals compared with control. At 48 h, it was found a several inflammatory response with neutrophils and lymphocytes, and a chronic inflammatory response characterized by the presence of macrophages and giant cells, at 3 weeks. The inflammatory response and the reabsorption of the nanoparticles were found decreased in diabetic group compared with the respective control group. It was observed the presence of a fibrous capsule in the experimental groups of the 3 weeks, but it was lower in the diabetic group as compared to the respective control group. There was also some aggregation of nano-Hap, that was more intense in both diabetic groups, and within these higher at 3 weeks. With the quantity tested, there has not been observed an overreaction and the biomaterial reabsorption occurred without signs of hepatic or renal toxicity. Although we observed a progressive reabsorption of nano-HAp throughout the experimental period, this process was significantly slower in diabetic conditions.
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Dissertação de Mestrado em Biologia Clínica Laboratorial
Palavras-chave
Regeneração óssea , Diabetes , Nano-HAp , Biocompatibilidade