Changes in microRNA expression in the brachial plexus avulsion model of neuropathic pain

The present study aimed to perform microRNA (miRNA/miR) expression profiling of the thalamus (T), the anterior cingulate (AC), the dorsal horn of the spinal cord (DHSC) and the blood (B) in post-complete brachial plexus avulsion (CBPA) pain model, and analyze biological functions. Neuropathic pain was induced in Sprague-Dawley rats by CBPA. Animal behavioral tests were performed to differentiate the pain and control groups. DHSC, T, AC and B tissues were collected from the two groups for miRNA array analysis. The predicted mRNA targets were investigated by Gene Ontology analysis and pathway analysis. The results revealed that in the post-CBPA pain model, there were 10 differentially expressed miRNAs revealed among 4 different tissues. A total of 4 microRNAs in the AC and 3 microRNAs in the T were shown to be significantly upregulated. The functions of the differentially expressed miRNAs in the AC and T were synergetic in the aspect of positive regulation of neuron apoptotic process, inhibition of long-term potentiation and formation of synapse plasticity. miR-30c-1-3p and its predicted genes [calcium/calmodulin dependent protein kinase IIβ (Camk2b) and protein kinase Cγ (Prkcg)] existed in the AC and T groups with significant changes in expression. There were 2 miRNAs in the DHSC and B groups, respectively, with significant downregulation. The function of the change in miRNAs in the DHSC group was opposite to that in the AC and T groups. The differentially expressed microRNAs in the B group were revealed to be negative for the regulation of cell apoptosis. In conclusion, the central nerve groups (AC and T) and the peripheral nerve group (DHSC) exhibited contrasting effects on synapse plasticity and neuron apoptosis. miR-30c-1-3p and its predicted genes (Camk2b and Prkcg) existed in the AC and T groups with significant changes in expression.