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

Tissue-engineered solution containing cells and biomaterials-an in vitro study: A perspective as a novel therapeutic application

Some biomaterial scaffolds can positively interfere with tissue regeneration and are being developed to successfully repair the tissue function. The possibility of using epithelial cells combined with biomaterials appears to be a new option as therapeutic application. This combination emerges as a possibility for patients with Mayer-Rokitansky-Kuster-Hauser syndrome which requires vaginal repair and can be performed with tissue-engineered solution containing cells and biomaterials. It is expected that tissue-engineered solution containing cells and biomaterials would promote tissue repair in a more efficient, modern, and safe way. This study tested the efficiency of tissue-engineered solution containing human malignant melanoma cell line (HMV-II) and different biomaterials, including Cellprene^®, Membracel^®, and poly lactic-co-glycolic acid/epoxidized polyisoprene. The cells adhered better on poly lactic-co-glycolic acid/epoxidized polyisoprene, and it was found that tissue-engineered solution may also contain mesenchymal stem cells cultivated on poly lactic-co-glycolic acid/epoxidized polyisoprene. Histological, immunofluorescence, and scanning electron microscopy analyses were performed. These initial in vitro results suggest that tissue-engineered solution containing cells and poly lactic-co-glycolic acid/epoxidized polyisoprene is a potential for tissue reconstruction.

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

Resumo Introdução A quantidade e qualidade óssea na implantodontia é um fator de alta relevância quando se tem por objetivo instalar implantes e reabilitar pacientes. No entanto, essa disponibilidade é comprometida na maioria dos casos, havendo a necessidade da busca de novos biomateriais, membranas e substâncias para uma regeneração mais favorável. Objetivo: O objetivo deste estudo foi avaliar a resposta da neoformação óssea em defeitos críticos em calvárias de ratos utilizando scaffolds de fibras de blenda polimérica a partir de poli (ácido láctico-co-glicólico) e poli-isopreno (Cellprene®). O projeto foi aprovado pelo Comitê de Ética em Experimentação Animal. Material e método Neste estudo, foram utilizados 36 ratos (Rattus Norvegicus), variação albinus, Holtzman, adultos. Os animais foram submetidos à tricotomia na região da calota craniana e à confecção de defeitos ósseos circulares bilaterais com 5 mm de diâmetro. Os animais foram divididos em três grupos: GC – defeito sem colocação de biomaterial; GCol – scaffolds de colágeno (Bio-Gide, da empresa Geistlich Pharma Ag – Biomaterials); GPoli – scaffolds de fibras de blenda polimérica a partir de poli (ácido láctico-co-glicólico - Cellprene®). Cada grupo foi avaliado em quatro períodos experimentais (7, 15, 30 e 60 dias). Após esses períodos, os animais foram sacrificados, e as peças passaram por tramitação laboratorial de rotina e inclusão em parafina. Foram obtidos cortes semisseriados e corados pela técnica de hematoxilina e eosina para análise histométrica e histológica. Foi executada análise histométrica para avaliar a composição do tecido ósseo reparado (% osso). Os dados obtidos foram analisados estatisticamente com nível de significância de 95%. Resultado Foi verificado que o GCol apresentou maior preenchimento do defeito nos períodos de 30 e 60 dias em comparação aos GC e GPoli. Conclusão Os scaffolds de fibras de blenda polimérica a partir de poli (ácido láctico-co-glicólico) e poli-isopreno (Cellprene®) não apresentaram vantagens quando utilizados em defeitos críticos.

Histological and structural evaluation of growth hormone and PLGA incorporation in macroporous scaffold of α-tricalcium phosphate cement

An in vivo study was conducted to evaluate the effects of the incorporation of fibers of poly(lactic acid-co-glycolic acid, PLGA) and poly(isoprene) blend and recombinant human growth hormone (rhGH) in a macroporous scaffold of α-tricalcium phosphate cement (α-TCP) samples inserted into calvarial defects (8 mm in diameter) of 48 Wistar rats. The samples of α-TCP + PLGA/poly(isoprene) blend fibers were also submitted to a mechanical test of flexural strength. The animals of the different experimental groups [1] α-TCP (n = 6); [2] α-TCP + PLGA/poly(isoprene) blend fibers (n = 6); [3] α-TCP + rhGH, (n = 6) and [4] α-TCP + PLGA/poly(isoprene) blend fibers + rhGH, (n = 6) (the numbers within square brackets identify the experimental groups), after two weeks (subdivision "a") and four weeks (subdivision "b"), were euthanized and the implants removed for histological analysis. There was no statistical difference (p > 0.05) between the samples with and without fibers in the mechanical test. Light microscopy revealed good integration of the material in the host tissue, represented by tissue penetration into the macropores and adequate angiogenesis. In the two-week period, the groups [3a] and [4a] were significantly superior (p < 0.05) to the other groups with regard to angiogenesis and bone neoformation. In the four-week period, the group [3b] was significantly superior (p < 0.05) to the other groups with regard to bone neoformation. We conclude that the macroporous α-TCP scaffold used in this study has low mechanical resistance, is biocompatible and has significantly improved the osteoconductive capacity when rhGH is incorporated into its structure.

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

The polymeric blend of poly (lactic-co-glycolic acid) (PLGA) and polyisoprene (PI) has recently been explored for application as stents for tracheal stenosis and spring for the treatment of craniosynostosis. From the positive results presented in other biomedical applications comes the possibility of investigating the application of this material as scaffold for tissue engineering (TE), acquiring a deeper knowledge about the polymeric blend by exploring a new processing technique while attending to the most fundamental demands of TE scaffolds. PLGA/PI was processed into randomly oriented microfibers through the dripping technique and submitted to physical-chemical and in vitro characterization. The production process of fibers did not show an effect over the polymer's chemical composition, despite the fact that PLGA and PI were observed to be immiscible. Mechanical assays reinforce the suitability of these scaffolds for soft tissue applications. Skeletal muscle cells demonstrated increases in metabolic activity and proliferation to the same levels of the control group. Human dermal fibroblasts didn't show the same behaviour, but presented cell growth with the same development profile as presented in the control group. It is plausible to believe that PLGA/PI fibrous three-dimensional scaffolds are suitable for applications in soft tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2581-2591, 2017.