Experimental comparative study of the histotoxicity of poly(lactic-co-glycolic acid) copolymer and poly(lactic-co-glycolic acid)-poly(isoprene) blend

Abstract

Current treatments of craniosynostosis rely on the application of metal springs for cranial bone deviation. However, those metal springs demand a second surgical procedure for their removal. An attractive alternative would be the substitution of metal for bioresorbable polymers in the composition of the springs. The addition of poly(isoprene), PI, to poly(lactic-co-glycolic acid), PLGA, produces a polymeric blend with partial miscibility and distinct mechanical behavior that may benefit the patient recover. It is necessary to compare the histotoxicity of PLGA/PI to that presented by PLGA. In order to verify the histological behavior of the blend, 46 male Wistar rats (Rattus norvegicus, albino strain) underwent implantation of PLGA or PLGA/PI in the skull and were allocated into subgroups by timing of euthanasia (15, 30, 60, or 90 days). After euthanasia, the skull was removed and the histotoxicity was assessed histopathologically. The PLGA/PI blend showed greater histotoxicity in animals euthanized at 60 days, although in this period the histotoxicity of the PLGA/PI blend was similar to that of the PLGA copolymer at 15 days. Despite the instability of histological response, presented in different periods of observation, the results obtained in long-term show that the material has high potential for studies in craniosynostosis treatment.

In vitro evaluation of poly (lactic‐co‐glycolic acid)/polyisoprene fibers for soft tissue engineering

“…76 As previously stated, in vivo applications of PLGA/PI blend have been related to the formation of intensively vascularised areas in bone tissue reconstruction. 34,35 This effect is strongly related to the presence of Poly(Isoprene) in the grafts, as previously observed in other applications. [77][78][79] This may indicate another desirable characteristic of this polymeric blend for dermal tissue engineering.…”

“…For that to be achieved, the use of angiogenic factors is essential in order to guarantee fast vascularisation on the treated area . As previously stated, in vivo applications of PLGA/PI blend have been related to the formation of intensively vascularised areas in bone tissue reconstruction . This effect is strongly related to the presence of Poly(Isoprene) in the grafts, as previously observed in other applications .…”

“…The idea of replacing the metallic springs with polymeric springs seeks the application of a material that will be better tolerated and posteriorly absorbed by the body, avoiding the need of a second surgical procedure to extract the device . Evaluating the cranial response in rats (Wistar) and rabbits (New Zealand), the springs made of PLGA/PI showed proper expansion of interbone space, biocompatibility with the bone environment and neovascularisation of areas surrounding the device …”

“…33 Evaluating the cranial response in rats (Wistar) and rabbits (New Zealand), the springs made of PLGA/PI showed proper expansion of interbone space, biocompatibility with the bone environment and neovascularisation of areas surrounding the device. 34,35 From the positive results presented in other biomedical applications comes the possibility of applying Cellprene TM in tissue engineering, acquiring a deeper knowledge about this material by exploring a new processing technique while attending to the most fundamental demands of TE scaffolds. Its mechanical properties may suggest this material to be more reliable as a scaffold for reconstruction of soft tissues, such as muscle, cartilage and skin.…”

Avaliação da combinação de poli (ácido láctico-co-glicólico) e poli-isopreno (Cellprene®): estudo histológico em ratos

“…Os polímeros sintéticos são obtidos industrialmente a partir de moléculas de baixo peso molecular, como o poli (ácido láctico-co-glicólico) (PLGA), um dos polímeros biorreabsorvíveis mais comuns, e o poli-isopreno (PI). O PLGA de forma isolada tem característica de fragilidade, porém, quando misturado ao PI, formando uma blenda, tem uma melhora nas suas propriedades mecânicas 9 . Esses materiais, ao serem degradados, podem liberar compostos de baixo peso molecular, entrando e atuando no sistema metabólico, e depois sendo excretados ou reabsorvidos 9 .…”