RhoA/ROCK pathway involved in effects of Sanjiao acupuncture on learning and memory and synaptic plasticity in Alzheimer's disease mice

Abstract

To observe the effect of Sanjiao acupuncture(triple energizer acupuncture)on the small G protein guanosine triphosphate enzyme subfamily protein RhoA/Rho kinase (ROCK) pathway in Alzheimer's disease mice, and explore its effect on learning and memory function and neurosynaptic plasticity. Forty SAMP8 senile dementia mice were randomly divided into model, Sanjiao acupuncture (acupuncture), non acupoint acupuncture (non-acupoint) and fasudil groups, with 10 mice in each group, another 10 SAMR normal aging mice were selected as normal aging group. Mice in the acupuncture group were treated with acupuncture intervention on "Danzhong"(CV18), "Zhongwan"(CV13), "Qihai"(BL24) and bilateral "Xuehai"(SP10) and "Zusanli" (ST36). Mice in the non-acupoint group were treated with acupuncture at each of the left and right non-acupoints under the ribs and mice in the fasudil group were intraperitoneally injected with fasudil (25 mg/kg). The mice in each group were given medicine or acupuncture on the second day after grouping for 28 continuously days, once a day. Morris water maze test was used to test the learning and memory ability of mice. HE staining was used to observe the pathological changes of neurons in hippocampus. The number of hippocampal neuron dendritic spine was detected by FD fast Golgi staining kit. The contents of β-amyloid 42 (Aβ42) and phosphorylated tau protein (p-tau) in hippocampus were detected by ELISA. Western blot was used to detect the protein relative expression levels of RhoA, ROCK, F-actin and p-cofilin in hippocampus. Compared with those in the normal aging group, the hippocampal neurons of the model group were disorderly arranged, the number of neuron was reduced, the escape latency, hippocampal Aβ42 and p-tau contents, RhoA and ROCK protein expressions increased (P<0.05), the number of crossing the original platform, the number of neuronal dendritic spines, expressions of F-actin and p-cofilin decreased (P<0.05). After the interventions, there was no statistically significant difference in the above indicators in the non-acupoint group relevant to the model group (P>0.05). The acupuncture group and fasudil group improved the hippocampal pathological damage. The escape latency, hippocampal Aβ42 and p-tau contents, the expressions of RhoA and ROCK protein decreased (P<0.05), and the number of crossing the original platform, the number of hippocampal neuron dendritic spines, expressions of F-actin and p-cofilin increased (P<0.05) in both of the acupuncture and fasudil groups in contrast to the model and non-acupoint groups. Compared with the acupuncture group, there was no significant difference in the above indicators in the fasudil group (P>0.05). Sanjiao acupuncture may inhibit the activation of the RhoA/ROCK pathway, so as to improve the learning and memory function of AD mice, increase the number of hippocampal neuron dendritic spines, and promote synaptic plasticity.