Sympathetic Nervous Activity is Involved in the Anti-Inflammatory Effects by Electroacupuncture Stimulation

Abstract

Increasing evidence suggests that parasympathetic vagus nerve activity plays a role in modulating acupunctureinduced anti-inflammatory reaction, but the function of sympathetic nerve is not known. Here, we investigated whether splanchnic sympathetic nerve activity was involved in the regulation of splenic expression of TNF-α mRNA by electroacupuncture (EA) in LPS-injected animals. Methods : DiI was injected into the stomach or celiac ganglion (CG) for retrograde labeling of the target tissues. EA was given at ST36 and the electrical stimulation on the sciatic nerve in LPS-injected mice. c-Fos signals in the tissues were analyzed by immunofluorescence staining, and TNF-α mRNA was analyzed by real-time PCR. Results : Application of EA at ST36 or electrical stimulation on the sciatic nerve induced c-Fos expression in neurons of the spinal cord and celiac ganglion (CG). Then, the vagotomy reduced c-Fos levels in CG neurons but not in the spinal cord in animals given EA. Expression of TNF-α mRNA which was induced in the spleen after LPS was significantly inhibited by EA, then the vagotomy elevated TNF-α mRNA level similar to that in LPS-injected animals. Splanchnectomy in animals given LPS and EA also increased TNF-α mRNA though it was less effective than vagotomy. Conclusions : Our data suggest that EA delivered to the spleen via the splanchnic sympathetic nerve may be involved in attenuating splenic inflammatory responses in LPS-injected animals.