Effect and mechanism of electroacupuncture intervention on radiation-induced hippocampal neuronal apoptosis in mice

Objective To investigate the effect and mechanism of electroacupuncture at acupoints on radiation-induced hippocampal neuronal apoptosis in C57 mice. Methods Forty one-month-old C57/6J mice were equally and randomly divided into control group, model group (8 Gy), acupoint-electroacupuncture group, and non-acupoint-electroacupuncture group. In the acupoint-electroacupuncture group, mice received electroacupuncture intervention at Baihui, Fengfu, and Shenshu points. The novel object recognition test was used to evaluate the cognitive, learning, and memory abilities in mice. Immunohistochemistry was used to determine the levels of caspase-3 and apoptosis-inducing factor (AIF). TUNEL assay was used to detect DNA breaks. The data were analyzed by one-way analysis of variance and the Tukey′s multiple comparison. Results Compared with the control group, the model group had a significantly reduced recognition index (P=0.040); compared with the model group, the acupoint-electroacupuncture group had a significantly increased recognition index (P=0.043), shown by significantly longer time spent exploring novel objects (P=0.035). According to the results of immunohistochemistry, the model group had significantly higher apoptosis rate and levels of caspase-3 and AIF in hippocampal neurons than the control group (P=0.002, 0.003, 0.023), while the acupoint-electroacupuncture group had significantly lower apoptosis rate and levels of caspase-3 and AIF in hippocampal neurons than the model group (P=0.027, 0.005, 0.004). Conclusions Radiation can induce hippocampal neuronal apoptosis and damage cognitive function in mice. Electroacupuncture intervention can, to some degree, reduce above damages. Key words: Irradiation; Electroacupuncture treatment; Hippocampus; Apoptosis