Upregulation of N-Type Voltage-Gated Calcium Channels Induces Neuropathic Pain in Experimental Autoimmune Neuritis

OBJECTIVE: Guillain–Barré syndrome (GBS) is a common autoimmune disease of the peripheral nervous system, and there is still no effective treatment for GBS. This investigation intends to figure out the effect and mechanism of N-type voltage-gated calcium (Cav2.2) channels on neuropathic pain in GBS. METHODS: An experimental autoimmune neuritis (EAN) model was established in Lewis rats induced by myelin P2(53-78) peptide and complete Freund's adjuvant. Luxol fast blue (LFB) staining was used for observing the degree of cell infiltration and demyelination in the sciatic nerve of rats, ELISA for detecting IL-6 and TNF-α expression in the serum, qRT-PCR, and Western blot for measuring the expression of iNOS, MCP-1, and Cav2.2 in the sciatic nerve, respectively. RESULTS: EAN led to significant decreases in the mechanical withdrawal threshold, thermal withdrawal threshold, and mechanical hyperalgesia threshold and an increase in the withdrawal threshold to cold stimulation. The serum IL-6 and TNF-α expression was significantly increased, and the mRNA and protein expression of iNOS, MCP-1, and Cav2.2 in the sciatic nerve were significantly increased in the EAN rats. However, silencing Cav2.2 expression could significantly reverse the above EAN-caused results. CONCLUSION: Silencing Cav2.2 expression can significantly reduce the clinical score, pathological injury, and mechanical allodynia, reducing the release of inflammatory factors, thus improving neuropathic pain in EAN rats.