Changes in expression of IB4 and CGRP in neurons in dorsal root ganglia of rats with neuropathic pain

Objective To evaluate the changes in the expression of isolectin B4 (IB4) and calcium gene-related peptide (CGRP) in neurons in dorsal root ganglion (DRG) of rats with neuropathic pain (NP). Methods Forty healthy male Sprague-Dawley rats, weighing 250-280 g, were divided into 2 groups (n=20 each) using a random number table method: solvent group (group S) and group NP.NP was induced by intraperitoneally injecting resiniferatoxin 210 μg/kg, and the solvent of resiniferatoxin was intraperitoneally injected in group S. The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured in 5 rats selected before establishing the model and at 1, 3, 7 and 42 days after establishing the model.Five rats were sacrificed at 1, 3, 7 and 42 days after establishing the model, and the L4-6 segments of the DRGs were removed to determine the expression of CGRP and IB4 in neurons using immunofluorescence. Results Compared with the baseline before establishing the model, the MWT was significantly decreased at 3, 7 and 42 days after establishing the model, and the TWL was prolonged at 1, 3, 7 and 42 days after establishing the model in group NP (P<0.05). Compared with group S, the MWT was significantly decreased at 3, 7 and 42 days after establishing the model, the TWL was prolonged at 1, 3, 7 and 42 days after establishing the model, and the expression of IB4 and CGRP in neurons in DRGs was down-regulated at 1, 3, 7 and 42 days after establishing the model in group NP (P<0.05). Conclusion Down-regulated expression of IB4 expression in neurons in DRGs may be involved in the development and maintenance of mechanical hypersensitivity to pain, and down-regulated expression of CGRP may be involved in the development and maintenance of thermal analgesia in rats with NP. Key words: Neuralgia; Ganglia, spinal; Plant lectins; Calcitonin gene-related peptide