Effect And Mechanism Of P38MAPK Signal Transduction Pathway In Electro-acupuncture Analgesia

Objective: to observe the influence of electro-acupuncture (EA) JIAJI points on p38 mitogen-activated protein kinase(p38MAPK), vanilloid receptor-1(VR1), nerve growth factor (NGF )in dorsal root ganglion(DRG) of complete Freund's adjuvant(CFA)arthritis rats and research the mechanism of electro-acupuncture analgesia through signal transduction pathway.Methods: Complete Freund's adjuvant was injected into the plantar surface of the left hindpaw of the SD rats to make the model of pain. The dual L3-L5 JIAJI points of the rats were given electro-acupuncture. Normal control group, CFA model group were used as control. Pain thresholds of each group were measured. Immunohistochemical technique was used to determine the change of phospho-p38MAPK, VRland NGF in DRG of all groups.Results: 1.Compare to normal control group, 24h, 48h, 7d after CFA injection in the plantar surface of rat left hind paw, the pain thresholds of CFA model group all declined(p<0.01).Pain thresholds of EA JIAJI points group rised in contrast to the CFA model group(p < 0.05) but had no significant difference between the normal control group(p>0.05).2.After making models 24h, 48h and 7d, the phospho-p38MAPK and NGF in DRG increased significantly (P<0.05) . While both in EA JIAJI points group decreased compare to the CFA model group (P<0.05 ) but had no significant difference between the normal control group(p>0.05). 3.The VR1 in DRG of CFA model group expressed heavily after injecting CFA into the plantar surface of rat left hind paw 48h (P<0.05) .while those in EA JIAJI points group decreased compare to the CFA model group (P<0.05).Conclusion: p38MAPK, VR1, NGF are important signal moleculars during electro-acupuncture analgesia. Electro-acupuncture can modulate the phosphorylation of p38MAPK, which contributed to acupuncture analgesia.