RESUMO
The aim of the present study was to investigate whether the cyclic adenosine 3',5'monophosphate (cAMP)/protein kinase A(PKA)/cAMPresponsive element binding protein (CREB) signal transduction pathway triggered by γaminobutyric acid class B (GABA(B)) receptor activation is involved in neuroprotection against ischemia and behavioral recovery induced by opposing needling (ON). A total of 80 rats were randomly divided into four groups: A sham operation group, an ischemia group, an ON group and an ON group effectively inhibited by the GABA(B) receptor antagonist, CGP35384 (n=20/group). The behavior of the rats was assessed by their neurological deficit score, whereas the impairment of gait was examined using the CatWalk system. The volume of cerebral infarction was examined upon treatment with 2,3,5triphenyltetrazolium chloride. The expression levels of CREB, GABA(B1) and GABA(B2) were examined by western blotting and reverse transcriptionquantitative polymerase chain reaction, and the activity of adenylyl cyclase (AC), cAMP and PKA in the serum was detected using an enzymelinked immunosorbent assay. In the present study, in comparison with other groups, the ON group exhibited a reduced score for the neurological deficit, the stride length and swing speed were improved, and the volume of infarction was reduced. However, these effects were reversed upon administration of CGP35384. Additionally, the expression levels of CREB, GABA(B1) and GABA(B2) were increased in the ON group. The levels of AC, cAMP and PKA in the serum were also increased in the ON group, whereas the addition of CGP35384 reversed these effects. The results of the present study demonstrated that ON markedly protected the brain against transient cerebral ischemic injury, and this effect was possibly mediated by the activation of the GABAB/cAMP/PKA/CREB signal transduction pathway. These findings implied that ON may be a potential therapeutic method for treating stroke.
Assuntos
Terapia por Acupuntura , Comportamento Animal , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , AMP Cíclico/metabolismo , Infarto da Artéria Cerebral Média/metabolismo , Neuroproteção , Transdução de Sinais , Adenilil Ciclases/sangue , Adenilil Ciclases/metabolismo , Animais , Infarto Encefálico/patologia , AMP Cíclico/sangue , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/sangue , Infarto da Artéria Cerebral Média/sangue , Infarto da Artéria Cerebral Média/patologia , Masculino , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo Real , Receptores de GABA-B/genética , Receptores de GABA-B/metabolismo , Traumatismo por Reperfusão/patologiaRESUMO
The aim of this study was to investigate the effect of electroacupuncture (EA) on cell proliferation and its molecular mechanisms. Sixty rats were randomly divided into 5 groups: sham operation control (SC), ischemia control (IC), EA, EA and DMSO injection (ED), EA and U0126 injection (EU). All the groups, with the exception of SC, underwent middle cerebral artery occlusion (MCAO), and DMSO or U0126 was injected into the rat in the ED or EU group 30 min prior to MCAO. Cell proliferation was evaluated by proliferating cell nuclear antigen (PCNA) immunostaining. The changes of cell cycle proteins (cyclin D1, CDK4, cyclin E, CDK2, p21 and p27) and the ERK1/2 pathway activation were examined by RT-PCR and western blot analysis. The results showed that the positive cell numbers of PCNA immunostaining in the EA and ED groups were more than those in the IC group (P<0.05). The mRNA and protein levels of p21 or p27 were obviously increased, however, the mRNA and protein levels of cyclin D1, CDK4, cyclin E and CDK2 were reduced in the IC and EU groups. The findings suggested that EA activates the ERK1/2 signaling pathway to protect brain injury during cerebral ischemia. However, this positive effect of EA can be blocked by U0126.
Assuntos
Eletroacupuntura/métodos , Neurônios/citologia , Neurônios/metabolismo , Animais , Butadienos/farmacologia , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Infarto da Artéria Cerebral Média/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Neurônios/efeitos dos fármacos , Nitrilas/farmacologia , Ratos , Ratos Sprague-DawleyRESUMO
We evaluated the neuroprotective effect of electro-acupuncture (EA) on cerebral ischemia-reperfusion (IR) injury and deeply investigated the relationship between this neuroprotective effect and PI3K/Akt pathway. Rats underwent focal cerebral IR injured by suture method and received the in vivo therapeutic efficacy of EA at points of Zusanli(ST36) and Quchi(LI11) after the operation. We found that the EA treatment significantly (p<0.05) improved neurological deficit and cerebral infarction. Furthermore, EA profoundly activated PI3K/Akt signaling resulted in the inhibition of cerebral cell apoptosis in the ischemic penumbra. Simultaneously EA increased the expression of PI3K, p-Akt, p-Bad and Bcl-2 at the protein level and the expression of Bcl-2 at the mRNA level. On the contrary, EA inhibited the Bax and cleaved Caspase-3-positive expression. The selective PI3K inhibitor LY294002 compromised EA-induced neuroprotective effects and reduced the elevation of p-Akt, p-Bad and Bcl-2 levels. Our data suggested that the PI3K/Akt pathway played a critical role in mediating the neuroprotective effects of EA treatment at points of Zusanli and Quchi after the ischemic stroke.