Exploration of the mechanism of action of cervical transverse process tip acupuncture for the treatment of rats with posterior circulation ischemic vertigo based on the Mas/PKA/CREB pathway.

Objective We aimed to explore the mechanism of action of cervical transverse process tip acupuncture in a rat model of posterior circulation ischemic vertigo (PCIV) based on the G protein-coupled receptor (Mas)/protein kinase A(PKA)/cyclophosphoadenosine effector binding protein (CREB) pathway. Methods According to the random number table method, 32 male SD rats were divided into the sham operation group (n=8), the model group (n=8), the nimodipine group (n=8), and the electroacupuncture group (n=8). In all groups except for the sham operation group, the PCIV model was established by ligating the right common carotid artery (CCA) and the right subclavian artery (SCA). In the sham operation group, only the right CCA and the right SCA were removed and sutured directly without ligation. The nimodipine group was given intragastric administration of nimodipine suspension (12 mg/kg), and the electroacupuncture group selected C2, C4, and C6 transverse process tip for acupuncture, and performed electroacup uncture treatment on both sides of C2 and C6, 20 minutes each time. There was no intervention in the sham operation group and the model group. The intervention was given once a day for 14 days. Cerebral blood flow, the decrease decline rate of cerebral blood flow, and the step-down avoidance time were recorded in each group. Apoptosis of neurons in the vestibular nucleus of the right brainstem was observed by TUNEL staining, and the protein expression levels of Mas, PKA-Ca, CREB, p-CREB, Bcl-2, and Bax in the vestibular nucleus of the right brainstem were determined by Western blotting. Results Before intervention, compared with the sham operation group, cerebral blood flow in the right vestibular nucleus was decreased and decline rate of cerebral blood flow in the right vestibular nucleus was increased in the remaining three groups (P<0.05), which suggested that the model was successfully established. After intervention, compared with the sham operation group, the model group showed lower cerebral blood flow in the right vestibular nucleus, larger decline rate of cerebral blood flow in the right vestibular nucleus, apoptosis rate in the vestibular nucleus of the right brainstem and protein expression level of Bax increased, and reduced protein expression levels of Bcl-2, Mas, PKA-Ca, and p-CREB/CREB (P<0.05). Compared with the model group, the electroacupuncture group and the nimodipine group showed increased cerebral blood flow in the right vestibular nucleus, a smaller decline rate of cerebral blood flow in the right vestibular nucleus, a shorter step-down avoidance time, a decrease in apoptosis rate in the vestibular nucleus of the right brainstem, decreased protein expression level of Bax, and increased protein expression levels of Bcl-2, Mas, PKA-Ca, and p-CREB/CREB (P<0.05). Compared with the nimodipine group, the electroacupuncture group had increased cerebral blood flow in the right vestibular nucleus, a smaller decline rate of cerebral blood flow in the right vestibular nucleus, a shorter step-down avoidance time, a decrease in apoptosis rate in the vestibular nucleus of the right brainstem, decreased protein expression level of Bax, and increased protein expression levels of Bcl-2, Mas, PKA-Ca, and p-CREB/CREB (P<0.05). Conclusion Cervical transverse process tip acupuncture can effectively inhibit apoptosis in the vestibular nucleus in rats with PCIV. Its mechanism may be related to improving cerebral blood flow of the vestibular nucleus and activation of the Mas/PKA/CREB signaling pathway, followed by the modulation of the levels of relevant proteins to inhibit apoptosis in the vestibular nucleus. [ABSTRACT FROM AUTHOR]