【Animal modeling】-Effect of bee venom on TrkA and TRPV1 in dorsal root ganglia of rats with collagen-induced arthritis inflammatory pain

  Objective: To investigate the effect of bee venom on TrkA and TRPV1 pain signaling molecules in collagen-induced arthritis rats.

  Methods: Divided into normal control group, model group and bee venom group (BV, 3 mg/mL). Wistar male adult rats were used to establish the model with Collagen Ⅱ+IFA 0.2 mL. In the BV group, administration was started 14 days after modeling until 21 days; the foot thickness, pain threshold and swollen joint scores were recorded in each group, and the expression of TRPV1 in pathological sections of the dorsal root ganglia and the expression of TrkA in the dorsal root ganglia were observed by IHC and western boltting. To evaluate the intervention of bee venom on the ankle joint of CIA rats.

  RESULTS: The model started to swell on the 10th day, and all signs of CIA appeared within 14 days. It became stable at 14 d. The BV group was treated with bee venom 0.3 mg for 7 days, and the foot thickness and swollen joint scores of the BV group were lower than those of the model group. Pain threshold (seconds): normal control group 15.47±0.35, model group 10.90±0.10, BV group 13.14±0.18. The percentage (%) of TRPV1 positive cells by immunohistochemistry: normal control group 11.40±1.48, model group 44.47±4.38, BV group 21.60±2.20. The expression of TrkA (gray value) was observed by western blotting: the normal control group was 1.59±0.04, the model group was 4.53±0.21, and the BV group was 2.46±0.17.

  Conclusion: Bee venom injection can reduce the expression levels of DRG signaling molecules TrkA and TRPV1 in rats with inflammatory pain. This may be one of the signaling pathways of anti-inflammatory and analgesic, providing new inspiration for bee venom in the treatment of rheumatoid arthritis.