Effect of 17?-estradiol on locomotor performance in rats subjected to spinal cord compression injury

Autor: Silva, Fernanda Kohn Bastos da
Přispěvatelé: Medeiros, Magda Alves de, Almeida, Norma Aparecida dos Santos, Resende, Victor T?lio Ribeiro de
Jazyk: portugalština
Rok vydání: 2014
Předmět:
Zdroj: Biblioteca Digital de Teses e Dissertações da UFRRJ
Universidade Federal Rural do Rio de Janeiro (UFRRJ)
instacron:UFRRJ
Popis: Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2019-09-30T18:08:36Z No. of bitstreams: 1 2014 - Fernanda Kohn Bastos da Silva.pdf: 2510739 bytes, checksum: 6ae960a9113ae4c42721c2a9f7eb2e81 (MD5) Made available in DSpace on 2019-09-30T18:08:36Z (GMT). No. of bitstreams: 1 2014 - Fernanda Kohn Bastos da Silva.pdf: 2510739 bytes, checksum: 6ae960a9113ae4c42721c2a9f7eb2e81 (MD5) Previous issue date: 2014-08-29 Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPQ Traumatic spinal cord injury promotes rapid cell death at the lesion epicenter and triggers a series of vascular, cellular and biochemical events, known as secondary damage, which culminate in more cell death, amplifying the injury and tissue dysfunction. The 17?-estradiol (E2) is an endogenous steroid hormone produced primarily by the gonads that has demonstrated neuroprotective effect in vitro and in vivo in several diseases and trauma to the central nervous system (CNS). E2 has shown multiple neuroprotective effects after spinal cord injury by modulating many secondary damage, such as: inflammation, apoptosis, oxidative stress and vascular changes. Accordingly, the aim of this study was to assess whether, acutely, the E2 promotes locomotor recovery in ovariectomized rats subjected to spinal cord compression injury. In the present study, female Wistar rats were subjected to bilateral ovariectomy (OVX) and after one week spinal cord injury was induced by inflation of a embolectomy catheter balloon (Fogarty 2F) with 15?l of saline into the epidural space between T8 and T9 vertebrae for 5 minutes. Fifteen minutes after spinal cord injury surgery a single dose of 100 ?g/Kg of E2 diluted in oil (OVX+E2 group) or oil vehicle alone (OVX+oil group) was administered subcutaneously. Some of the animals were subjected to OVX and after a week was performed only spinal laminectomy (OVX+sham group). The locomotor performance of the animals was assessed using the BBB test for 14 days and it was detected significant improvement in locomotor recovery in OVX+E2 group compared to OVX+oil group at 10 and 14 days after spinal cord injury. To verify that better locomotor ability of animals treated with E2 is related with the least amount of damage to the spinal cord tissue, the cross-sections of the histopathological analysis of spinal cord tissue of these animals was performed. The histopathological evaluation detected that the OVX+E2 group showed significantly less tissue damage under the aspects of length, width and area of the lesion compared to OVX+oil group. Accordingly, the results suggest that E2 is able to promote locomotor recovery after a mild compression injury to the spinal cord, and this effect is associated with a reduction of the damage to the spinal cord tissue, supporting the hypothesis that E2 is a neuroprotective hormone Uma les?o traum?tica na medula espinal promove r?pida morte celular no epicentro da les?o e desencadeia uma s?rie de eventos vasculares, celulares e bioqu?micos, denominados danos secund?rios, que culminam em morte de c?lulas que estavam intactas ap?s o trauma inicial e, desta forma, amplifica a les?o e a disfun??o tecidual. O 17?-estradiol (E2) ? um horm?nio esteroide end?geno produzido principalmente pelas g?nadas e que tem demonstrado efeito neuroprotetor in vitro e in vivo, em diversas doen?as e traumas no sistema nervoso central (SNC). Na les?o medular espinal o E2 tem evidenciado m?ltiplas a??es neuroprotetoras por modular diversos danos secund?rios ? les?o, tais como: inflama??o, apoptose, estresse oxidativo e altera??es vasculares. Nesse sentido, o objetivo desse estudo foi avaliar se, de forma aguda, o E2 promove recupera??o locomotora em ratas ovariectomizadas submetidas ? les?o medular por compress?o. Neste estudo foram utilizadas ratas Wistar que foram submetidas a ovariectomia bilateral (OVX) e ap?s uma semana foi induzida a les?o medular atrav?s da infla??o do bal?o de um cateter Fogarty 2F de embolectomia, inflado com 15?l de solu??o salina no espa?o epidural entre as v?rtebras T8 e T9 durante 5 minutos. Quinze minutos ap?s a cirurgia de les?o medular foi administrado por via subcut?nea uma dose ?nica de 100 ?g/Kg de E2 dilu?do em ?leo (grupo OVX+E2) ou somente o ve?culo ?leo (grupo OVX+?leo). Uma parte dos animais foi submetida a OVX e ap?s uma semana foi realizada apenas a laminectomia vertebral (grupo OVX+sham). A performance locomotora dos animais foi avaliada atrav?s do teste BBB durante 14 dias e foi detectado uma significativa melhora na recupera??o locomotora do grupo OVX+E2 comparado ao grupo OVX+?leo no 10? e 14? dia ap?s a les?o medular. Para verificar se essa melhor capacidade locomotora dos animais tratados com E2 esta relacionada com a menor quantidade de les?o no tecido medular, foi realizada a an?lise histopatol?gica de cortes longitudinais de tecido medular desses animais. Na avalia??o histopatol?gica da medula foi detectado que o grupo OVX+E2 apresentou les?es significativamente menores sob os aspectos de comprimento, largura e ?rea da les?o comparado ao grupo OVX+?leo. Nesse sentido, os resultados sugerem que o E2 ? capaz de promover recupera??o locomotora ap?s uma les?o moderada na medula espinal, sendo esse efeito associado ao menor tamanho de les?o no tecido, corroborando com a hip?tese de que o E2 ? um horm?nio neuroprotetor.
Databáze: OpenAIRE
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