Estudo da interação polímero/cartilagem/osso utilizando poli (ácido lático-co-ácido glicólico) e poli (p-dioxanona) em condilo femural de coelhos

Abstract

Os dispositivos biorreabsorvíveis são alternativas para fixação interna das fraturas. Durante o tratamento estes dispositivos mantêm a fixação e degradam-se gradualmente não necessitando de uma cirurgia de remoção, reduzindo o custo de tratamento quando comparadas aos dispositivos metálicos. O objetivo desse trabalho foi estudar a interação polímero/tecido utilizando pinos de PLGA e PDS após implantes em coelhos Nova Zelândia. Separou-se os animais em 3 grupos os quais foram sacrificados após 3, 6 e 12 semanas de implantação e o material obtido foi submetido à análise histológica. As análises histológicas com implantes de PLGA mostraram após 3 semanas a formação de um tecido com características mesenquimatosas e com 12 semanas a formação de uma estrutura óssea madura. Já nos implantes de PDS de 3 semanas houve uma maior invasão de tecido mesenquimal comparado ao PLGA e após 12 semanas, ocorreu uma degradação avançada, com tecido proliferativo mesenquimal e ósseo. Assim, concluiu-se que ocorreram resultados positivos à resposta tecidual/implante e foi relevante a observação da ausência de células responsáveis pela resposta inflamatória. As análises demonstraram que o copolímero de PLGA apresentou propriedades osteoindutivas mais adequadas que os de PDS, apresentando biocompatibilidade aceitável para aplicação ortopédica.

The use of PLDLA/PCL-T scaffold to repair osteochondral defects in vivo

“…Our results agree with other reports showing that a four-week interval after implantation is insufficient for osteochondral regeneration; in this period, only the initial performance of the scaffold and the occurrence of an inflammatory response can be evaluated [35][36][37][38] . In contrast, bone neoformation is readily observed 12 weeks after the implantation of PLGA and PLLA 18,35 . Fedrizzi and Duek 28 showed that PLDLA/PCL-T (90/10 composition) pins were sufficiently biocompatible for bone regeneration in tibia and this polymer combination held promising prospects for osteochondral applications.…”

“…However, this reaction is of minimal importance for tissue neoformation since it disappears after the complete degradation and bioreabsorption of the polymer 18,20,21,[26][27][28][29] . Porous scaffolds can be prepared by several techniques and have a useful morphology for tissue engineering since their porosity provides physical space for cell growth and colonization.…”

“…In addition, the material must have favorable biomechanical properties to provide an environment that allows the cells to integrate, differentiate and develop into new tissue 15 . The polymers most widely studied for biomedical applications are poly(α-hydroxy) acids, primarily because of suitable properties related to degradation, bioreabsorption and biocompatibility [16][17][18] . The copolymer poly(L-co-D,L-lactic acid), PLDLA, combines the mechanical properties of poly(lactic acid) without the long degradation time normally associated with the homopolymer (caused by the high crystallinity of the latter); the higher degradation rate is provided by poly(D,L-lactic acid), although the mechanical properties of this molecule are somewhat inferior to those of poly (lactic acid).…”

Biological Evaluation of PLDLA Polymer Synthesized as Construct on Bone Tissue Engineering Application

“…We have reported the synthesis and development of a number of bioreabsorbable polylactide-based polymers obtained by ring-opening polymerization of lactide and glycolide monomers [7][8][9][10] . Their potential use as biomedical devices and their biocompatibility with skin, bone, cartilage and neuronal tissue also have been explored [11][12][13][14][15] . Among the polymers synthesized by the group, we highlight the amorphous copolymer poly(L-co-D,L lactide)-PLDLA which has molecular weight range of 10 5 g/mol and glass transition temperature of 55-60 o C 8,16 .…”

Isolation and characterization of bacterial producers of optically pure D(-) and L(+) lactic acid

“…One of the most important applications of lactic acid is in the production of biodegradable materials, such as polylactate (PLA), which is used in the production of bags, computers components (Ohara, 2003), food packaging and plastic utensils. As PLA is bioabsorbable material, it is also employed in medicine in the regeneration of tissues, sutures, repairs and implants (Sakata et al, 2004). Polymers produced with D(-) and L(+) lactic acid have properties similar to plastics produced from fossil reserves, but offer the ad-vantage of a high degree of biodegradability.…”