ABSTRACT
OBJECTIVES: To investigate the mechanism of electroacupuncture (EA) in alleviating cerebral ische-mia injury by activating the Yap-OPA1 signaling axis. METHODS: A total of 48 male SD rats were used in the present study. The focal CIRI model was established by occlusion of the middle cerebral artery and reperfusion (MCAO/R), followed by dividing the CIRI rats into model group, EA group and EA+Ver (Verteporfin, Yap antagonist) group (n=12 in each group). And another 12 normal rats were used as the sham operation group. For rats of the EA group, EA (4 Hz/20 Hz, 0.5 mA) was applied to "Baihui"(GV20) and "Shenting"(GV24) for 20 min, once daily for 7 days. The neurological deficit score (0 to 4 points) was given according to Longa's method. The infarct volume of rats in each group was assessed by TTC method, and the expression levels of Yes associated protein (Yap), Optic atrophy protein 1 (OPA1), mitofusin 1 (Mfn1), mitofusin 2 (Mfn2) proteins and mRNAs in cerebral cortex of infarcted side, as well as Bax (proapoptotic factor) and Bcl-1 (anti-apoptotic protein) proteins were detected by Westernblot, and real-time PCR, and the immunoactivity of Yap and OPA1 was detected by immunofluorescent staining. RESULTS: After modeling, the infarct volume, neurological deficit score and the expression of Bax were significantly increased (P<0.01), while the mRNA and protein expressions of Yap, OPA1, Mfn2, Mfn1, and Bcl-2 were significantly down-regulated in the model group relevant to the sham operation group (P<0.01, P<0.05). Compared with the model group, the neurological deficit score, infarct volume and the expression of Bax were significantly decreased (P<0.01), while the expression levels of Yap, OPA1, Mfn2, Mfn1 proteins and mRNAs and Bcl-2 protein, Yap and OPA1 immunofluorescence intensify were considerably up-regulated in the EA group (P<0.01, P<0.05). Following administration of Ver, the effects of EA in down-regulating the neurological score, infarct volume, and Bax expression and up-regulating the expressions of Yap, OPA1, Mfn1, Mfn2 proteins and mRNAs and Yap and OPA1 immunofluorescence intensify were eliminated. CONCLUSIONS: EA of GV20 and GV24 can improve the neurological function in rats with CIRI, which may be associated with its functions in activating mitochondrial fusion function and up-regulating Yap-OPA1 signaling axis.
Subject(s)
Brain Ischemia , Electroacupuncture , Reperfusion Injury , Rats , Male , Animals , Rats, Sprague-Dawley , Brain Ischemia/genetics , Brain Ischemia/therapy , Mitochondrial Dynamics , bcl-2-Associated X Protein , Reperfusion Injury/genetics , Reperfusion Injury/therapy , InfarctionABSTRACT
OBJECTIVE: To investigate the mechanism of electroacupuncture in alleviating cerebral ischemia injury in cerebral ischemia-reperfusion rats by regulating melatonin - NOD-like receptor protein 3 (NLRP3) mediated pyroptosis. METHODS: A total of 48 SD rats were randomly divided into sham operation group, model group, electroacupuncture (EA) group and EA +Luz group, with 12 rats in each group. The focal cerebral ischemia-reperfusion injury model was established by middle cerebral artery embolization. Rats of the EA group was treated with EA stimulation (4 Hz/20 Hz, 0.5 mA,20 min) at "Baihui" (GV20) and "Shenting" (GV24) once a day for 7 consecutive days; rats of EA+Luz group were given the same EA treatment and intraperitoneally administered melatonin receptor antagonist (luzindole, 30 mg/kg), once a day for 7 consecutive days. The neurological impairment was evaluated by Zea Longa score. The level of serum melatonin content at 12:00 and 24:00 was detected by ELISA. The percentage of cerebral infarction volume was evaluated by MRI of small animals. The apoptosis rate of nerve cells in cerebral cortex of infarct side was detected by TUNEL staining. The activation of microglia cells was detected by immunofluorescence staining. The expression levels of pyroptosis-related proteins NLRP3, Caspase-1 and interleukin (IL) -1ß were detected by Western blot. RESULTS: Compared with the sham operation group, the neural function score was significantly increased (P<0.01); the melatonin content was significantly decreased at 24:00 (P<0.01); the percentage of cerebral infarction volume, apoptosis rate of nerve cells in cerebral cortex area of infarction side, the expressions of NLRP3, Caspase-1 and IL-1ß proteins were significantly increased (P<0.01); and microglia cells were significantly activated in the model group.Compared with the model and EA +Luz groups, the nerve function score was significantly decreased (P<0.05); the percentage of cerebral infarction volume, the nerve cell apoptosis rate, the activation level of microglia cells, the expression levels of NLRP3, Caspase-1 and IL-1ß were significantly decreased (P<0.01, P<0.05) in the EA group. Compared with the model and EA+Luz groups, the melatonin content at 24:00 was significantly increased (P<0.01, P<0.05) in the EA group. CONCLUSION: EA at GV20 and GV24 can reduce the neurolo-gical injury in cerebral ischemia reperfusion model rats, which may be related to regulating the expression of endogenous melatonin, inhibiting cell scorchification and reducing cerebral ischemia injury.
Subject(s)
Brain Injuries , Brain Ischemia , Electroacupuncture , Melatonin , Reperfusion Injury , Rats , Animals , Rats, Sprague-Dawley , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , Pyroptosis , Reperfusion Injury/genetics , Reperfusion Injury/therapy , Brain Ischemia/genetics , Brain Ischemia/therapy , Cerebral Infarction/genetics , Cerebral Infarction/therapy , Caspase 1/geneticsABSTRACT
OBJECTIVE: To observe the effect of electroacupuncture(EA)at "Baihui"(GV20) and "Shenting" (GV24) on the expression of melatonin synthesis rate-limiting enzyme-arylalkylamine N-acetyltransferase(AANAT)in pineal gland of rats with focal cerebral ischemia-reperfusion injury, so as to explore the mechanism of EA underlying improving ischemia-reperfusion injury. METHODS: Forty-eight SD rats were randomly divided into sham operation, model, EA and non-acupoint groups, with 12 rats in each group. The focal cerebral ischemia-reperfusion injury rat model was established by occlusion of the middle cerebral artery. Rats of the EA group received EA at GV20 and GV24, while those in the non-acupoint group received EA at non-acupoints below the costal margins on both sides for 20 min, once daily for 7 days. The neurological deficit score (0 to 4 points) was given after successful modeling according to Longa's method. Morris water maze test was used to assess the cognitive function of rat. ELISA was used to detect the plasma melatonin content, and PCR and Western blot were used to detect the mRNA and protein expressions of AANAT in the pineal gland, separately. Immunofluorescence staining was used to detect the activation of astrocytes and neuronal injury in the hippocampus. RESULTS: After focal cerebral ischemia-reperfusion injury and compared with the sham operation group, the neurological deficit score, the escape latency, and the expression of GFAP were significantly increased (P<0.01)ï¼while the times of platform quadrant crossing, the secretion of melatonin at 24:00ï¼AANAT mRNA and protein expression levels and NeuN protein expression were significantly down-regulated (P<0.01). After EA at GV20 and GV24, the above-mentioned indexes all reversed in the EA group relative to the model group, and there were significant differences between the two groups(P<0.01). Compared with the model group, the changes of the abovementioned indexes in the non-acupoint group were not statistically significant (P>0.05). CONCLUSION: EA at GV20 and GV24 can alleviate neurological deficit and improve cognitive function in cerebral ischemia-reperfusion ratsï¼which may be related to its effects in up-regulating endogenous melatonin levels, inhibiting the activation of astrocytes and protecting damaged neurons in the hippocampus.