Background: Thalamic pain (TP), also known as central post-stroke pain, is a chronic neuropathic pain syndrome that follows a stroke and is a severe pain that is usually intractable. No universally applicable and effective therapies have been proposed. Emerging studies have reported that electroacupuncture (EA) can potentially be used as an effective therapy for the treatment of neuropathic pain. However, whether EA influences TP and if so, by what potential mechanism, remains poorly understood.
Objective: The aim of this study was to detect the efficacy of EA and explore possible mechanisms for treating TP.
Study design: Controlled animal study.
Setting: The laboratory at the Aviation General Hospital of China Medical University and Beijing Institute of Translational Medicine.
Methods: Male Sprague Dawley rats were randomly divided into 3 groups (n = 15 / group): sham-operated (SH) group, thalamic pain model (TP) group, EA treatment (EA) group. After the TP rat model was successfully established, EA was used for intervention. During the experiment, the mechanical pain thresholds of rats were detected among the groups. The right thalamus of the rats was extracted on postoperative day 28 for RNA-sequencing (RNA-Seq) analysis to find the changes in gene expression in different groups of rats. The key genes were screened using reverse transcription-polymerase chain reaction (RT-PCR) detection and subsequently identified with western blotting and immunofluorescence.
Results: The mechanical withdrawal threshold (MWT) value of the right facial skin in the TP group and the EA group decreased significantly on the 3rd day after surgery, compared to the SH group (P < 0.01). From 7 to 28 days, the MWT value increased continually in the EA group; however, there was no significant change in the TP group. The results of RNA-seq showed that compared to the TP group, 377 genes changed in the EA group. Moreover, ADCY1 expression increased significantly in the TP group as compared to the SH group, while EA treatment reversed the expression of ADCY1.
Limitations: In addition to ADCY1, the mechanism(s) of other signaling pathways in TP need to be explored in future research.
Conclusions: EA treatment may promote the recovery of TP model rat by regulating ADCY1 expression.
Keywords: ADCY1; Gene Ontology; Kyoto Encyclopedia of Genes and Genomes; RNA-sequencing analysis; cobra venom; electroacupuncture; neuropathic pain; Thalamic pain.