Análise das fibras musculares do músculo sóleo de rato após reconstrução nervosa periférica: efeito da associação do selante heterólogo de fibrina à sutura
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Data
2021-07-21
Autores
Palone, Maria Antonia Monteiro
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Universidade Estadual Paulista (Unesp)
Resumo
Os nervos são os principais constituintes do Sistema Nervoso Periférico, com frequência, são acometidos por lesões cujas causas mais comuns são: traumas, estiramento, pinçamento, compressão e esmagamento. As lesões nervosas periféricas (LNPs) levam à interrupção da condução nervosa e afetam, além do nervo, o músculo. Ocorrem diversas alterações estruturais, funcionais e moleculares; além de atrofia. Apesar dos avanços nas técnicas cirúrgicas a recuperação após este tipo de lesão raramente é completa. Métodos alternativos de reconstrução vêm sendo utilizados, entre eles o selante heterólogo de fibrina. Assim, o objetivo deste trabalho foi avaliar os efeitos da associação do selante heterólogo de fibrina à sutura na reconstrução nervosa com foco nas fibras musculares, aos 7 e 30 dias após lesão do nervo isquiático. Foram utilizados 40 ratos Wistar machos adultos, divididos em 4 grupos experimentais: Controle Sham (CS); Controle Desnervado (CD); Lesão + Sutura (LS); Lesão + Sutura + Biopolímero de Fibrina (LSB). No grupo CS foi realizada apenas incisão superficial no antímero direito com localização do nervo isquiático. No grupo CD foi realizada neurotmese do nervo isquiático (gap de 6 mm). No grupo LS após neurotmese os cotos foram religados com 2 pontos de sutura. No grupo LSB, a reconstrução foi realizada por 2 pontos de sutura seguida da aplicação do biopolímero. Decorridos 30 dias, os animais foram anestesiados e eutanasiados. Os músculos sóleos direitos foram coletados para a realização da análise morfológica (HE) e morfométrica das fibras musculares (área, perímetro, diâmetros máximo e mínimo, angulação, circularidade e contagem de núcleos centrais). Aos 7 dias não houve diferença morfológica entre os grupos, em relação à morfometria o grupo CS apresentou maior valor de diâmetro mínimo quando comparado aos demais (CD, LS, LSB). Já aos 30 dias, o grupo CD apresentou aglomerados de pequenas fibras musculares, algumas delas com núcleo central. A morfometria, não mostrou diferenças em relação à angulação e circularidade da fibra muscular. Já os valores de área, diâmetro mínimo e diâmetro máximo foram maiores no grupo Controle Sham (CS) quando comparados aos demais (CD, LS, LSB). O número de núcleos centrais foi maior no grupo CD quando comparado aos grupos CS e LSB. Destaca-se o número de núcleos centrais do grupo LSB semelhante ao grupo CS e diferente do grupo CD. Os resultados mostram-se promissores, mas são necessários mais estudos para indicar a redução ou substituição das suturas como tratamento para LNPs.
Nerves are the main constituints of the Peripheral Nervous System. Frequently, they suffer physical trauma through striation, pinching, compression and crushing. Peripheral nerve injuries (PNI) lead to interruption of nerve conduction and also affect muscles, causing a series of structural, funcional and molecular alterations, in addition to atrophy. Despite advanced surgical techniques, this kind of injury is rarely fully healed. Alternative reconstruction methods have been implemented, among them, the heterologous fribrin sealant. With that in mind, the object of this study was to avaliate the effects of associating the heterologous fibrin sealant to the suture when reconstructing damaged nerves, focusing on muscle fibers, 7 and 30 days after injury of the ischiatic nerve. This study used 40 adult male Wistar rats, split into 4 experimental groups: Sham Control (SC); Denerved Control (DC); Injury+Suture (IS); Injury+Suture+Sealant (ISS). The SC group suffered only a superficial incision on the right antimer, on the ischiatic nerve. The DC group suffered complete neurotmesis of the ischiatic nerve (6mm gap). The IS group also suffered complete neurotmesis of the ischiatic nerve, but the stubs were sutured back together with 2 stitches. On the ISS group, the reconstruction was done through two suture stitches followed by application of the sealant. After the set time, the animals were anesthetized and euthanized. The soleus muscles were collected for morphological analysis (HE) and morphometry of the muscle fibers (area, perimeter, maximum and minimum diameter, angulation, circularity and central nucleus count). After 7 days, there were no morphological difference between the groups, but in regards to morphometry, the SC group showed greater fiber diameter when compared to the other groups. After 30 days, the DC group presented clusters of small muscle fibers, some of them with central nuclei. The morphometrical analysis didn't find differences regarding angulation and circularity of the fibers, but found that the SC group had greater area, minimum diameter and maximum diameter when compared to the other groups. A greater number of central nuclei were also found on the DC group when compared to the SC and ISS groups, but the number of central nuclei found in the ISS group was similar to the SC and different from the DC group. The results found in the study are promissing, but more research is necessary in order to reduce or completely replace suture as a treatment to PNIs.
Nerves are the main constituints of the Peripheral Nervous System. Frequently, they suffer physical trauma through striation, pinching, compression and crushing. Peripheral nerve injuries (PNI) lead to interruption of nerve conduction and also affect muscles, causing a series of structural, funcional and molecular alterations, in addition to atrophy. Despite advanced surgical techniques, this kind of injury is rarely fully healed. Alternative reconstruction methods have been implemented, among them, the heterologous fribrin sealant. With that in mind, the object of this study was to avaliate the effects of associating the heterologous fibrin sealant to the suture when reconstructing damaged nerves, focusing on muscle fibers, 7 and 30 days after injury of the ischiatic nerve. This study used 40 adult male Wistar rats, split into 4 experimental groups: Sham Control (SC); Denerved Control (DC); Injury+Suture (IS); Injury+Suture+Sealant (ISS). The SC group suffered only a superficial incision on the right antimer, on the ischiatic nerve. The DC group suffered complete neurotmesis of the ischiatic nerve (6mm gap). The IS group also suffered complete neurotmesis of the ischiatic nerve, but the stubs were sutured back together with 2 stitches. On the ISS group, the reconstruction was done through two suture stitches followed by application of the sealant. After the set time, the animals were anesthetized and euthanized. The soleus muscles were collected for morphological analysis (HE) and morphometry of the muscle fibers (area, perimeter, maximum and minimum diameter, angulation, circularity and central nucleus count). After 7 days, there were no morphological difference between the groups, but in regards to morphometry, the SC group showed greater fiber diameter when compared to the other groups. After 30 days, the DC group presented clusters of small muscle fibers, some of them with central nuclei. The morphometrical analysis didn't find differences regarding angulation and circularity of the fibers, but found that the SC group had greater area, minimum diameter and maximum diameter when compared to the other groups. A greater number of central nuclei were also found on the DC group when compared to the SC and ISS groups, but the number of central nuclei found in the ISS group was similar to the SC and different from the DC group. The results found in the study are promissing, but more research is necessary in order to reduce or completely replace suture as a treatment to PNIs.
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Palavras-chave
Músculo esquelético, Biopolímeros, Fibrina, Adesivo tecidual de fibrina, Nervos periféricos doenças