2023, Vol. 27 ›› Issue (26): 4139-4146

Expression of microRNA-124 and cortical proteins in ischemic penumbra of rats pretreated with “Tongdu Tiaoshen” electroacupuncture

Zhang Junyu1, Zhang Lida2, Hu Yanqi3, Jin Zikai4, Luo Fuci5, Wu Xiaoqing6, Tong Tingting6, Song Xiaoge7, Han Wei1   

Abstract: BACKGROUND: “Tongdu Tiaoshen” electroacupuncture pretreatment is an emerging physiotherapy combining traditional acupuncture with modern electrical stimulation, which has been reported to have significant therapeutic effects on ischemic stroke, but its specific mechanism is still unclear.
OBJECTIVE: To investigate the effects of “Tongdu Tiaoshen” electroacupuncture pretreatment on cell apoptosis, the relative expression of microRNA-124 (miR-124) in the ischemic penumbra and Notch-1, p-JNK and cysteinyl-aspartate specific protease-3 (caspase-3) proteins in the cortex of rats and their possible mechanisms of action.
METHODS: Seventy-five male Sprague-Dawley rats were randomly divided into five groups (n=15 per group): model group, sham-operated group, electroacupuncture pretreatment group, miR-124 antagomir pretreatment group and electroacupuncture+miR-124 agomir pretreatment group. In the electroacupuncture pretreatment group, 20-minute electroacupuncture at Fengchi, Baihui, and Dazhui was performed once a day, for 7 continuous days. In the miR-124 antagomir pretreatment group, miR-124 antagomir was injected into the lateral ventricle of rats on day 7. In the electroacupuncture+miR-124 agomir pretreatment group, miR-124 agomir was injected based on electroacupuncture pretreatment. Model and sham-operated groups were not treated. After the intervention, animal models were created. In the sham-operated group, the rats were only fixed on the operating board and the vessels were blunt-separated. In the other groups, the right cerebral ischemia-reperfusion injury model was established by the middle cerebral artery occlusion method and the Zea Longa suture method. Twenty-four hours after the modeling, the modified neurological severity scoring was performed to determine the damage. TUNEL staining method was then used to measure cell apoptosis in the rat cerebral cortex. Ultrastructure of the rat cerebral cortex was observed under electron microscopy.
RESULTS AND CONCLUSION: Compared with the sham-operated group, the modified neurological severity scores were significantly elevated in the other groups (all P < 0.01). Compared with the model group, the miR-124 antagomir pretreatment group and electroacupuncture pretreatment group had significantly reduced modified neurological severity scores (both P < 0.05). Compared with the sham-operated group, the number of apoptotic cells was elevated in the model group (P < 0.01). Compared with the model group, the number of apoptotic cells was reduced in the pretreatment groups (all P < 0.01). The model group had more severe defects in cell structure and contents. The electroacupuncture pretreatment group had mild defects in cell structure and contents. Cells in the miR-124 antagomir pretreatment group were more intact. There was damage to cell structure and contents in the electroacupuncture+miR-124 agomir pretreatment group. The relative expressions of caspase-3, Notch-1 and p-JNK proteins in the cortex of rats were significantly lower in the miR-124 antagomir pretreatment and electroacupuncture pretreatment group compared with the model group (all P < 0.01). The relative expression of miR-124-3p and Notch-1 mRNA in the cortex of the pretreated rats was significantly reduced compared with that of the model group (all P < 0.01). The relative expression of caspase-3 mRNA and p-JNK mRNA in the cortex of rats was significantly reduced in the miR-124 antagomir pretreatment and electroacupuncture pretreatment groups compared with the model group (all P < 0.01). The relative expression of p-JNK mRNA in the cortex of rats in the electroacupuncture+miR-124 agomir pretreatment group was also reduced compared with the model group (P < 0.05). To conclude, “Tongdu Tiaoshen” electroacupuncture pretreatment can inhibit the apoptosis of neuronal cells after cerebral ischemia-reperfusion injury by interfering with the expression level of miR-124 in the brain tissue of rats, thereby reducing neurological deficits after cerebral ischemia-reperfusion injury. The mechanism of this action may be related to the positive regulation mechanism of miR-124 on the Notch pathway.

Key words: cerebral ischemia-reperfusion injury, apoptosis, microRNA-124, Tongdu Tiaoshen, Notch signaling pathway