A dexametasona administrada pela via subaracnoidea é toxica à medula espinal e meninges de coelhos?
Carregando...
Arquivos
Data
2018-02-21
Autores
Moroto, Denise
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Introdução: Dor perioperatória desencadeia resposta neuroendócrina ao estresse, responsável por efeitos adversos em vários órgãos e sistemas. Estratégias foram desenvolvidas para controle da dor e dessa resposta ao trauma, como a injeção de dexametasona, glicocorticoide de alta potência, no espaço peridural e subaracnoideo. Embora a injeção de corticosteroides no neuroeixo seja realizada com aparentes benefícios em seres humanos no contexto da dor aguda e crônica, a eficácia e segurança desse procedimento continuam discutíveis e alvo de controvérsia na literatura. O objetivo deste estudo foi avaliar os efeitos histológicos que a dexametasona administrada no espaço subaracnoideo determina sobre o tecido nervoso da medula espinal e das meninges dos coelhos. Método: Após aprovação pela Comissão de Ética no Uso de Animais, 28 coelhos adultos jovens foram randomizados em dois grupos (G) experimentais com 14 animais cada: G1 recebeu solução salina a 0,9% pela via subaracnoidea e G2, dexametasona na dose de 0,37 mg.kg-1. Os animais foram mantidos em cativeiro por 21 dias, durante os quais se avaliou motricidade e sensibilidade dolorosa. Depois desse período, sob anestesia venosa, foram submetidos a sacrifício para retirada da porção lombar e sacral da medula espinal e das meninges para avaliação histológica pelo método de Hematoxilina-eosina (HE) e de marcação imuno-histoquímica para Proteína Glial Fibrilar Ácida (GFAP). Resultados: Todos os animais permaneceram sem alterações clínicas durante o período de cativeiro. Nenhum animal do G1 apresentou alterações histológicas à microscopia óptica. No G2, 13 animais exibiram infiltrado inflamatório linfoplasmocitário perivascular nos vasos das meninges, com ou sem acometimento também das meninges e do parênquima nervoso. Os animais do G2 também tiveram percentual de células marcadas pelo GFAP inferior aos do G1 (p<0,05). Conclusão: Neste modelo experimental em coelhos, a solução de dexametasona determinou alterações histológicas no tecido nervoso da medula espinal e, principalmente, nas meninges.
Background: Perioperative pain triggers neuroendocrine response to stress, responsible for adverse effects on various organs and systems. Strategies were developed to control pain and this response to trauma, such as the injection of dexamethasone, a high-potency glucocorticoid, into the epidural and subarachnoid space. Although corticosteroid spinal injection is performed with apparent benefits in humans in the context of acute and chronic pain, the efficacy and safety of this procedure remain controversial in the literature. The objective of this study was to evaluate the histological effects that dexamethasone administered into the subarachnoid space determines on the nervous tissue of the spinal cord and the meninges of rabbits. Methods: After approval by the animal research ethics committee, 28 young adult rabbits were randomized in two experimental groups (G) with 14 animals each: G1 received 0.9% saline solution into the intrathecal space and G2 received 0.37mg.kg-1 of dexamethasone by the same route. The animals were clinically evaluated for 21 days. After this period of observation, sacrifice was performed under intravenous anesthesia and then the lumbar and sacral portion of their spinal cords were removed for histological examination by Hematoxylin-eosin (HE) and Glial Fibrillary Acidic protein (GFAP) immunohistochemical staining. Results: All animals remained without clinical changes during the period of captivity. No histological changes were observed in G1 animals. In G2, 13 animals exhibited perivascular lymphoplasmocytic inflammatory infiltrate in the meninges vessels, with or without involvement of the meninges and the nervous parenchyma. G2 animals also showed lower percentage of GFAP stained cells than rabbits of G1 (p<0.05). Conclusion: In this experimental model, the dexamethasone solution determined histological changes in the nervous tissue of the spinal cord and, especially, the meninges of rabbits.
Background: Perioperative pain triggers neuroendocrine response to stress, responsible for adverse effects on various organs and systems. Strategies were developed to control pain and this response to trauma, such as the injection of dexamethasone, a high-potency glucocorticoid, into the epidural and subarachnoid space. Although corticosteroid spinal injection is performed with apparent benefits in humans in the context of acute and chronic pain, the efficacy and safety of this procedure remain controversial in the literature. The objective of this study was to evaluate the histological effects that dexamethasone administered into the subarachnoid space determines on the nervous tissue of the spinal cord and the meninges of rabbits. Methods: After approval by the animal research ethics committee, 28 young adult rabbits were randomized in two experimental groups (G) with 14 animals each: G1 received 0.9% saline solution into the intrathecal space and G2 received 0.37mg.kg-1 of dexamethasone by the same route. The animals were clinically evaluated for 21 days. After this period of observation, sacrifice was performed under intravenous anesthesia and then the lumbar and sacral portion of their spinal cords were removed for histological examination by Hematoxylin-eosin (HE) and Glial Fibrillary Acidic protein (GFAP) immunohistochemical staining. Results: All animals remained without clinical changes during the period of captivity. No histological changes were observed in G1 animals. In G2, 13 animals exhibited perivascular lymphoplasmocytic inflammatory infiltrate in the meninges vessels, with or without involvement of the meninges and the nervous parenchyma. G2 animals also showed lower percentage of GFAP stained cells than rabbits of G1 (p<0.05). Conclusion: In this experimental model, the dexamethasone solution determined histological changes in the nervous tissue of the spinal cord and, especially, the meninges of rabbits.
Descrição
Palavras-chave
dexametasona, punção subaracnoidea, neurotoxicidade, coelho, toxicidade meníngea, dexamethasone, intrathecal injection, neurotoxicity syndrome, rabbits, spinal anesthesia