Dados do Trabalho

Título/Title/Titulo

Application of FGF-2/PLGA microfibers in spinal cord tissue engineering

Introdução/Introduction/Introdución

Spinal cord injury (SCI) is a major public health issue that affects approximately 2.5 million patients worldwide. A promising approach for treatment is represented by the use of scaffolds, which can provide a structural support able to bridge the gap between the lesion and the injury site. Basic fibroblast growth factor (FGF-2) promotes SCI tissue repair but is easily degradable and presents collateral effects in systemic administration.

Objetivos - Metodologia - Resultados - Discussão dos Resultados/Objectives - Methodology - Results - Discussion of Results/Objetivos - Metodología - Resultados - Discusión de los resultados

Aim
In order to address the stability issue and avoid the systemic effects, FGF-2 was encapsulated into core-shell microfibers by coaxial electrospinning and its in vivo potential was studied in a hemisection rat model of SCI.

Methodology
The morphology and diameter of the fibers were characterized by scanning electron microscopy. The microfibers were implanted in a hemisection SCI rat model. The study was approved by the local ethics committee. The animals were divided into three groups (1) SCI control, (2) PLGA scaffold and (3) FGF-2/PLGA scaffold. Locomotor test was performed weekly for 6 weeks. After this time, histological analyses were performed and expression of nestin and GFAP was quantified by flow cytometry.

Results and discussion
The results demonstrated that coaxial electrospinning resulted in a uniform microfiber morphology. The groups that received implanted scaffolds showed the tendency to have higher scores in the locomotor evaluation than the SCI control group. A significant difference was observed 28 days after SCI in the PLGA scaffold and FGF-2/PLGA scaffold groups when compared to the SCI control. The addition of FGF-2 into the microfibers seemed to have no better effect than the PLGA scaffold alone on the locomotor recovery after SCI. This result suggests a lower amount of FGF-2 was delivered from the microfibers. Therefore, only the presence of the scaffolds was sufficient to promote functional recovery. The histological analysis showed incomplete degradation of the scaffold and the presence of tissue in the hemisection cavity. The existence of a scaffold at the injury site is important to support tissue regeneration, that is, the scaffold degradation should occur in a timely fashion allowing the regenerated nerve tissue to become mature enough to be self-supporting. There was a decrease in GFAP expression in the scaffold groups compared to the SCI control. This result indicates a reduction in glial scaring at the local lesion. There was no significant difference of the number of nestin expressing cells among the groups.

Considerações Finais/Final considerations/Consideraciones finales

These results indicate the potential of the microfiber scaffolds to promote locomotor recovery after spinal cord injury and a reduction in glial scaring at the injury site. Therefore, the studied scaffolds have an excellent potential in SCI tissue engineering. However, it is necessary to increase the concentration of the FGF-2 within the microfibers to observe the synergetic effects of the scaffolds and the growth factor in this model.

Acknowledgments: CAPES, CNPQ, FINEP, MCTI, and Stem Cell Research Institute (IPCT)

Palavras-chave/Key words/Palabras clave

spinal cord injury, FGF-2, coaxial electrospinning