RESUMEN
Dantrolene has been shown to be neuroprotective by reducing neuronal apoptosis after brain injury in several animal models of neurological disorders. In this study, we investigated the effects of dantrolene on experimental spinal cord injury (SCI). Forty-six male Wistar rats were laminectomized at T13 and divided in six groups: GI (n = 7) underwent SCI with placebo and was euthanized after 32 h; GII (n = 7) underwent laminectomy alone with placebo and was euthanized after 32 h; GIII (n = 8) underwent SCI with dantrolene and was euthanized after 32 h; GIV (n = 8) underwent SCI with placebo and was euthanized after 8 days; GV (n = 8) underwent laminectomy alone with placebo and was euthanized after 8 days; and GVI (n = 8) underwent SCI with dantrolene and was euthanized after 8 days. A compressive trauma was performed to induce SCI. After euthanasia, the spinal cord was evaluated using light microscopy, TUNEL staining and immunochemistry with anti-Caspase-3 and anti-NeuN. Animals treated with dantrolene showed a smaller number of TUNEL-positive and caspase-3-positive cells and a larger number of NeuN-positive neurons, both at 32 h and 8 days (P ≤ 0.05). These results showed that dantrolene protects spinal cord tissue after traumatic SCI by decreasing apoptotic cell death.
Asunto(s)
Antígenos Nucleares/metabolismo , Apoptosis/efectos de los fármacos , Dantroleno/uso terapéutico , Proteínas del Tejido Nervioso/metabolismo , Traumatismos de la Médula Espinal/tratamiento farmacológico , Médula Espinal/efectos de los fármacos , Análisis de Varianza , Animales , Caspasa 3/metabolismo , Recuento de Células , Dantroleno/farmacología , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Laminectomía , Masculino , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neuronas/patología , Distribución Aleatoria , Ratas , Ratas Wistar , Recuperación de la Función , Médula Espinal/metabolismo , Médula Espinal/patología , Traumatismos de la Médula Espinal/metabolismo , Traumatismos de la Médula Espinal/patologíaRESUMEN
This work aimed at determining the ideal ischemia time in an in vitro ischemia-reperfusion model of spinal cord injury. Rat spinal cord slices were prepared and then exposed or not to oxygen deprivation and low glucose (ODLG) for 30, 45, 60, 75 and 90 minutes. Cell viability was assessed by triphenyltetrazolium (TTC), lactate dehydrogenase (LDH) release, and fluorochrome dyes specific for cell dead (ethidium homodimer) using the apotome system. Glutamate release was enzymatically measured by a fluorescent method. Gene expression of apoptotic factors was assessed by real time RT-PCR. Whereas spinal cord slices exposed to ODLG exhibited mild increase in fluorescence for 30 minutes after the insult, the 45, 60, 75 and 90 minutes caused a 2-fold increase. ODLG exposure for 45, 60, 75 or 90 minutes, glutamate and LDH release were significantly elevated. nNOS mRNA expression was overexpressed for 45 minutes and moderately increased for 60 minutes in ODLG groups. Bax/bcl-xl ratio, caspase 9 and caspase 3 mRNA expressions were significantly increased for 45 minutes of ODLG, but not for 30, 60, 75 and 90 minutes. Results showed that cell viability reduction in the spinal cord was dependent on ischemic time, resulting in glutamate and LDH release. ODLG for 45 minutes was adequate for gene expression evaluation of proteins and proteases involved in apoptosis pathways.
Asunto(s)
Modelos Animales de Enfermedad , Daño por Reperfusión/metabolismo , Isquemia de la Médula Espinal/metabolismo , Animales , Apoptosis/fisiología , Supervivencia Celular/fisiología , Técnicas de Cultivo de Órganos , Ratas , Ratas Wistar , Reacción en Cadena en Tiempo Real de la Polimerasa , Transducción de Señal/fisiología , Factores de TiempoRESUMEN
O tramadol é um analgésico opióide usado em medicina veterinária, embora existam poucos estudos sobre este fármaco. O objetivo deste trabalho foi avaliar o efeito analgésico promovido pela administracão do tramadol, mensurando o cortisol sérico e a glicemia de cadelas. Para isso, foram utilizadas 15 fêmeas, submetidas a ovário-histerectomia sob anestesia geral com isofluorano. Os animais foram divididos em três grupos. Grupo 1 (Tep) receberam tramadol pela via epidural (1,0mg kg-1 diluído em água bidestilada ao volume final de 3,0mL) e, após 15 minutos, 3,0mL de água bidestilada pela via intravenosa. No grupo 2 (Tiv), foi administrado 3,0mL de água bidestilada pela via epidural e, após 15 minutos, tramadol pela via intravenosa (1,0mg kg-1 diluído em água bidestilada ao volume final de 3,0mL). No grupo 3 (CT), os animais receberam 3,0mL de água bidestilada pela via epidural e, após 15 minutos, 3,0mL de água bidestilada pela via intravenosa. A eficácia de cada regime analgésico foi avaliada durante 12 horas após a administracão da injecão epidural. Não houve diferenca significativa entre os grupos experimentais para as variáveis estudadas (P>0,05). Foram observadas diferencas significativas dentro de cada tratamento. No grupo Tep houve aumento do cortisol sérico aos 25 minutos do trans-operatório (M3), em relacão ao valor obtido imediatamente após a inducão anestésica (M2) (P>0,05). Nos tratamentos Tiv e CT, verificou-se elevacão das variáveis, duas (M4) e quatro (M5) horas da injecão epidural (P<0,05), quando comparadas ao pré-tratamento (M1). Nesses períodos, as variáveis estudadas no tratamento Tep foram estatisticamente semelhantes ao pré-tratamento (M1). Com base nos resultados, conclui-se que: 1) a metodologia empregada foi sensível para determinar os momentos de maior estresse cirúrgico, dentre os estudados e 2) o tramadol por via epidural produz analgesia mais duradoura quando comparado à administracão intravenosa.