Effects of Mongolian medical warm acupuncture on model rats with insomnia based on positron emission tomography-computed tomography (PET-CT)

Objective: Insomnia is one of the most common sleep disorders, with a very high morbidity. Mongolian medicine is characterized by a unique theory, presenting favorable therapeutic effects in the treatment of insomnia. In Mongolian medicine, warm acupuncture is ubiquitously applied for treatment of insomnia. It can invigorate bodily functions, regulate qi, blood, and somatostatin, strengthen immunity, and prevent and treat multiple diseases. The current study aimed to explore the effects of Mongolian medical warm acupuncture on cerebral glucose metabolism in insomnia rats using the PET-CT technique. Materials and methods: Rats were injected with para-chlorophenylalanine (PCPA) to establish the insomnia model. Rats were randomly divided into the normal group, model group, and warm acupuncture group, which received tail intravenous injections of 18F-FDG for scanning imaging of PET/CT. Expression of NDRG2 was detected with Western blotting. Differential expression of microRNAs in the brain tissues of the insomnia rats, before and after Mongolian medical warm acupuncture, was detected for qPCR verification. Plasmids were transfected to neurocytes of the rats for dual-luciferase reporter assay examination. Expression of NDRG2 was detected with the immunohistochemical method. Relevant cytokines and neurotransmitters were detected with ELISA. Results: Glucose metabolism in the Mongolian medical warm acupuncture group was strengthened, compared with that in the model group. Present results showed significant differences in the effects of Mongolian medical warm acupuncture, which plays a promoting role in cerebral function activity of model rats with insomnia via activating most regions inhibited in the brain. Chip data analysis found that expression of 156 miRNAs in the rats treated with Mongolian medical warm acupuncture was obviously altered. Of which, levels of miR-181a were increased by 3.2 times, compared with those in the model group. In silico analysis with TargetScan, PicTar, and miRanda showed that miR-181a and NDRG2 might have a target regulation relationship. Results of luciferase assay in 293T cells indicated no significant changes in the MUT-NDRG2-3'UTR group, while fluorescence intensity in the WT group was decreased significantly, following addition of miR-181a mimics. Western blotting results indicated that expression of NDRG2 in neuronal cells of the model rats with insomnia was significantly downregulated at 72 hours, after addition of miR-181a mimics, compared to that in the scramble group (P<0.01). Administration of warm acupuncture reduced volume shrinkage. Rod-like fusion occurred in NDRG2-positive cells of the rats, while expression of NDRG2, particularly in the neuron cytoplasm, was downregulated, compared to that in model group. Levels of IL-1, IL-2, IL-6, and TNF-alpha in the warm acupuncture group increased significantly, compared with those in the model group (P<0.05). Warm acupuncture significantly increased levels of GABA and reduced levels of Glu, compared with the insomnia model group. Conclusion: Mongolian medical warm acupuncture plays a promoting role in glucose metabolism in the brain of the model rats with insomnia. It upregulates levels of miR-18 and reduces NDRG2 levels, providing an academic basis for modern development of the traditional ethnic medicine.