RESUMEN
Subarachnoid hemorrhage (SAH) is the most devastating form of stroke. Reducing neuronal apoptosis is an important countermeasure against early brain injury (EBI) after SAH. Recent evidence indicates that OX40-OX40L coupling is critical for cell survival and proliferation. Current study was performed to detect the role of recombinant OX40 (ReOX40) against neuronal apoptosis after SAH. The endovascular perforation model of SAH was performed on Sprague-Dawley (SD) rats. ReOX40 was injected intracerebroventricularly (i.c.v) 1 h after SAH induction and the following methods were employed: neurological function evaluation, immunofluorescence staining, fluoro-Jade C staining, and western blot. To study the underlying precise molecular mechanism, small interfering ribonucleic acid (siRNA) for OX40L and a specific inhibitor of PI3K, LY294002, were injected i.c.v. into SAH + ReOX40 rats before induction of SAH. When compared with sham rats, the expression of OX40 and OX40L was seen to decrease in the brain at 24 h after SAH induction. Administration of ReOX40 (5 µg/kg) increased expression of the OX40L, reduced the neuronal apoptosis, and improved short and long-term neurological function deficits. Furthermore, ReOx40 heightened activation of OX40L/PI3K/AKT axis, increased the downstream anti-apoptotic protein (Bcl2, Bcl-XL), and depressed the apoptotic protein (cleaved caspase 3, Bax). However, the protective effects of ReOX40 were abolished by the administration of OX40L siRNA and LY294002, respectively. These results demonstrate that ReOX40 attenuates neuronal apoptosis through OX40-OX40L/PI3K/AKT pathway in EBI after SAH.
Asunto(s)
Apoptosis/efectos de los fármacos , Neuronas/efectos de los fármacos , Receptores OX40/uso terapéutico , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Hemorragia Subaracnoidea/tratamiento farmacológico , Hemorragia Subaracnoidea/genética , Animales , Proteínas Reguladoras de la Apoptosis/biosíntesis , Proteínas Reguladoras de la Apoptosis/genética , Inyecciones Intraventriculares , Masculino , Glicoproteínas de Membrana/antagonistas & inhibidores , Proteína Oncogénica v-akt/antagonistas & inhibidores , Fosfatidilinositol 3-Quinasas/genética , Inhibidores de Proteínas Quinasas/uso terapéutico , ARN Interferente Pequeño/uso terapéutico , Ratas , Ratas Sprague-Dawley , Receptores OX40/farmacología , Proteínas Recombinantes/farmacología , Proteínas Recombinantes/uso terapéutico , Factores de Necrosis TumoralRESUMEN
AIM: To determine the effect of osteopontin (OPN) on autophagy and autophagy-apoptosis interactions after SAH. METHODS: The endovascular perforation model of SAH or sham surgery was performed in a total of 86 Sprague-Dawley male rats. The temporal expressions of endogenous OPN and autophagy-related proteins (Beclin 1, ATG5, LC3 II to I ratio) were measured in sham and SAH rats at different time points (3, 6, 12, 24, and 72 hours). Rats were randomly divided into three groups: Sham, SAH + Vehicle (PBS, phosphate-buffered saline), and SAH + rOPN (5 µg/rat recombinant OPN). Neurobehavioral tests were performed 24 hours after SAH, followed by the collection of brain samples for assessment of autophagy and apoptosis proteins. These tests assessed whether an autophagy-apoptosis relationship existed on the histological level in the brain. RESULTS: Endogenous OPN and autophagy-related proteins all increased after SAH. rOPN administration improved neurological dysfunction, increased the expression of autophagy-related proteins (Beclin 1, ATG5, LC3 II to I ratio) and antiapoptotic protein Bcl-2, while decreasing the expression of proapoptotic proteins (cleaved Caspase-3 and Bax). rOPN also regulated autophagy-apoptosis interactions 24 hours after SAH. CONCLUSION: rOPN attenuates early brain injury and inhibits neuronal apoptosis by activating autophagy and regulating autophagy-apoptosis interactions.
