Physical exercise may help maintain muscle properties and functional improvement after peripheral nerve lesion, which may be enhanced by using biocompatible substances, such as sericin. The aim of this study was analyse the effect of sericin associated with swimming exercise on the phenotype, innervation, and functionality of the plantar muscle of Wistar rats. Forty randomly divided adult rats were used in five groups of eight animals: control, injury, sericin, exercise, exercise and sericin. The application of sericin was done on the spot, 100 μL, shortly after nerve compression. Three days after sciatic nerve compression, the swimming and swimming and sericin groups were submitted to physical swimming exercise for 21 days. Afterwards, the animals were euthanised and the plantar muscle was dissected and submitted to histochemical and histoenzymological techniques. The grip strength test did not show alterations in muscular functionality, and the control presented greater muscle mass in relation to the other groups, the same did not occur for muscle length. Polymorphic neuromuscular junctions were detected in the groups, although without significant morphometric alterations of the area, major and minor diameters. The percentage of type I fibres was lower in the lesion group and there was no difference in fibres IIa and IIb between groups. The area of fibres I, IIa and IIb remained constant between groups. Sericin biopolymer combined with swimming exercise did not affect plantar muscle function, submitted to experimental axonotmosis, whose contractile properties were altered by nerve injury.

ObjectiveTo analyze the combined effects of the silk protein sericin and swimming exercise on histomorphometry of the plantar muscle in Wistar rats.MethodsForty adult rats were randomly allocated into 5 groups comprising 8 animals each, as follows: Control, Injury, Sericin, Swim, and Swim plus Sericin. Three days after crushing of the sciatic nerve the rats in the Swim and Swim plus Sericin Groups were submitted to swimming exercise for 21 days. Rats were then euthanized and the plantar muscle harvested and processed.ResultsCross-sectional area, peripheral nuclei and muscle fiber counts, nucleus/fiber ratio and smallest muscle fiber width did not differ significantly between groups. Morphological analysis revealed hypertrophic fibers in the Swim Group and evident muscle damage in the Swim plus Sericin and Injury Groups. The percentage of intramuscular collagen was apparently maintained in the Swim Group compared to remaining groups.ConclusionCombined treatment with sericin and swimming exercise did not improve muscle properties. However, physical exercise alone was effective in maintaining intramuscular connective tissue and preventing progression of deleterious effects of peripheral nerve injury.

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O esteroide anabolizante caracteriza-se por melhorar o desempenho atlético. O decanoato de nandrolona, usado no tratamento de condições clínicas associadas com a perda de massa muscular, é estimulante na regeneração nervosa periférica e na aceleração na recuperação funcional. O presente estudo tem por objetivo realizar uma revisão sistemática referente à regeneração nervosa periférica com o uso da nandrolona. Foram consultadas as bases de dados Pubmed, Medline, Scielo e Google Acadêmico, utilizando as seguintes palavras-chave: “anabolic steroids”, “nandrolone”, “nerve regeneration”, “denervation”, “reinnervation” “nerve injury” e “nerve repair”, bem como seus análogos em português. Foram encontrados 3 trabalhos que atenderam os requisitos. Apesar das diferenças metodológicas, dois deles indicaram resultados significativos quanto ao uso do decanoato de nandrolona na regeneração nervosa e o terceiro uma tendência positiva. Há necessidade de novas pesquisas para levar a conclusões mais específicas em relação ao uso da nandrolona no processo de regeneração nervosa.Palavras-chave: nandrolona, esteroides, neurite, força muscular.