Reconstrução nervosa via neurorrafia associada ao biopolímero heterólogo de fibrina: avaliação da resposta inflamatória e interação neuromuscular
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Data
2021-07-22
Autores
Tibúrcio, Felipe Cantore [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
As lesões nervosas periféricas (LNPs) afetam, além do nervo, a inervação do músculo e as junções neuromusculares (JNMs) associadas. Ocorrem diversas alterações morfofuncionais e moleculares, além de uma intensa resposta imune, principalmente macrofágica. Métodos alternativos de reparo vêm sendo utilizados a fim de potencializar a regeneração nervosa como o biopolímero heterólogo de fibrina (BHF). O objetivo desse estudo foi avaliar os efeitos do BHF associado à neurorrafia no reparo do nervo isquiático, com ênfase no microambiente da lesão e na interação neuromuscular. Quarenta ratos Wistar (CEUA/IBB/Unesp: 1177/2019) foram distribuídos em 4 grupos (n = 10/grupo). No grupo Controle (C) foi realizada a localização do nervo. No grupo Desnervado (D), neurotmese e remoção de fragmento de 6 mm, inversão dos cotos e fixação na tela subcutânea. No grupo Sutura (S), neurotmese seguida de neurorrafia. No grupo Sutura + BHF (SB), neurotmese seguida de neurorrafia e acrescido o BHF. Os animais foram eutanasiados aos 7 e 30 dias após cirurgia. Os nervos e os músculos sóleos foram coletados para análise semiquantitativa dos macrófagos M2 (CD206+); análise morfológica e morfométrica do nervo, do músculo e das JNMs; quantificação de tecido conjuntivo intramuscular. O grupo SB foi o único que apresentou semelhança ou maior proximidade ao grupo C, em relação ao número de axônios aos 7 dias; e ao número, área e densidade dos vasos sanguíneos, angulação e ângulo de Feret das JNMs, número de núcleos centrais e quantificação de tecido conjuntivo do músculo, aos 30 dias. Também aos 7 dias no grupo SB, houve aumento da área do nervo, número e área dos vasos sanguíneos em relação aos outros grupos. E ainda no grupo SB aos 7 e 30 dias houve aumento da área dos macrófagos M2 em relação a todos os outros grupos. Esses resultados demonstram o potencial do BHF em acelerar a regeneração nervosa, induzir angiogênese e potencializar a resposta imune, além de prevenir degeneração muscular severa, com menor grau de fibrose e auxiliar no retorno das JNMs aos seus padrões morfológicos normais O BHF fornece um microambiente favorável, que melhora a regeneração nervosa, e assim, vantajoso no reparo de nervos periféricos.
Peripheral nerve injuries (PNIs) affect, in addition to the nerve, muscle innervation and associated neuromuscular junctions (NMJs). There are several morphofunctional and molecular changes, in addition to an intense immune response, mainly macrophagic. Alternative repair methods have been used in order to enhance nerve regeneration, such as the heterologous fibrin biopolymer (HFB). The purpose of this study was to evaluate the effects of HFB associated with neurorrhaphy on sciatic nerve repair, with emphasis on the microenvironment of the injury and on neuromuscular interaction. Forty Wistar rats (CEUA/IBB/Unesp: 1177/2019) were distributed into 4 groups (n = 10/group). In the Control group (C), the location of the nerve was performed. In the Denervated group (D), neurotmesis and removal of a 6 mm fragment, inversion of the stumps and fixation in the subcutaneous tissue. In the Suture (S) group, neurotmesis followed by neurorrhaphy. In the Suture + BHF (SB) group, neurotmesis followed by neurorrhaphy plus BHF. Animals were euthanized at 7 and 30 days after surgery. The nerves and soleus muscles were collected for semiquantitative analysis of macrophages M2 (CD206+); morphological and morphometric analysis of the nerve, muscle and NMJs; quantification of intramuscular connective tissue. Group SB was the only one that showed similarity or greater proximity to group C, in relation to the number of axons at 7 days; and the number, area and density of blood vessels, angulation and Feret angle of NMJs, number of central nuclei and quantification of muscle connective tissue, at 30 days. Also at 7 days in the SB group, there was an increase in the nerve area, number and area of blood vessels in relation to the other groups. And even in the SB group at 7 and 30 days there was an increase in the area of M2 macrophages compared to all other groups. These results demonstrate the potential of BHF in accelerating nerve regeneration, inducing angiogenesis and potentiating the immune response, in addition to preventing severe muscle degeneration with a lower degree of fibrosis and helping to return NMJs to their normal morphological patterns, which improves nerve regeneration, and thus is advantageous in peripheral nerve repair.
Peripheral nerve injuries (PNIs) affect, in addition to the nerve, muscle innervation and associated neuromuscular junctions (NMJs). There are several morphofunctional and molecular changes, in addition to an intense immune response, mainly macrophagic. Alternative repair methods have been used in order to enhance nerve regeneration, such as the heterologous fibrin biopolymer (HFB). The purpose of this study was to evaluate the effects of HFB associated with neurorrhaphy on sciatic nerve repair, with emphasis on the microenvironment of the injury and on neuromuscular interaction. Forty Wistar rats (CEUA/IBB/Unesp: 1177/2019) were distributed into 4 groups (n = 10/group). In the Control group (C), the location of the nerve was performed. In the Denervated group (D), neurotmesis and removal of a 6 mm fragment, inversion of the stumps and fixation in the subcutaneous tissue. In the Suture (S) group, neurotmesis followed by neurorrhaphy. In the Suture + BHF (SB) group, neurotmesis followed by neurorrhaphy plus BHF. Animals were euthanized at 7 and 30 days after surgery. The nerves and soleus muscles were collected for semiquantitative analysis of macrophages M2 (CD206+); morphological and morphometric analysis of the nerve, muscle and NMJs; quantification of intramuscular connective tissue. Group SB was the only one that showed similarity or greater proximity to group C, in relation to the number of axons at 7 days; and the number, area and density of blood vessels, angulation and Feret angle of NMJs, number of central nuclei and quantification of muscle connective tissue, at 30 days. Also at 7 days in the SB group, there was an increase in the nerve area, number and area of blood vessels in relation to the other groups. And even in the SB group at 7 and 30 days there was an increase in the area of M2 macrophages compared to all other groups. These results demonstrate the potential of BHF in accelerating nerve regeneration, inducing angiogenesis and potentiating the immune response, in addition to preventing severe muscle degeneration with a lower degree of fibrosis and helping to return NMJs to their normal morphological patterns, which improves nerve regeneration, and thus is advantageous in peripheral nerve repair.
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Palavras-chave
Adesivo tecidual de fibrina, Resposta imune, Junção neuromuscular, Sistema nervoso regeneração, Nervos periféricos, Biopolímero de fibrina, Regeneração nervosa, Lesão nervosa periférica, Fibrin biopolyme, Immune response