Objective: To observe the effects of acupoint-nerve block on manual-acupuncture (MA) and electroacupuncture (EA) analgesia and mast cells degranulation in adjuvant arthritis (AA) rats in order to analyze the underlying peripheral mechanism of MA and EA analgesia.
Methods: A total of 80 SD rats were randomized into control, AA model (M), normal + lidocaine (NL), EA, EA-ST36 + Lidoc (L + EA), Dubi (ST 35) + Lidoc + EA-ST36 (DL + ZEA), Xiajuxu (ST 39) + Lidoc + EA-ST36 (XL+ ZEA), MA, Lidoc+ MA-ST36 (L + MA), and ST35 + Lidoc + MA-ST36 (DL + ZMA) groups, with 8 cases in each. AA model was established by injection of complete Freund's adjuvant (0.05 ml) in the rat's right hind-paw under anesthesia. Lidoc hydrochloride (2%, 0.05 ml) was injected into ST36 or ST35 separately for blocking the local nerve. Paw withdrawal latency (pain threshold, PT) and mast cell degranulation ratios (DGR) were detected. EA (2/100 Hz, 0.5 mA, 1 mA, 1.5 mA) or MA was applied to ST36.
Results: Compared with model group, PT values of EA and MA groups increased significantly (P<0.05, P<0.01) and mast cell DGR of EA and MA groups were significantly higher (P<0.01). Both PT and DGR of NL group were basically not affected by ST36-Lidoc-injection in comparison with model group (P>0.05). PT values of L + EA and DL+ ZEA groups were significantly lower than those of control and EA groups (P<0.01), and comparable to those of model and NL groups (P>0.05). PT of XL + ZEA group was significantly higher than those of model and NL groups (P<0.01), and comparable to that of EA group (P>0.05). Similar situations were found in MA-related groups. Mast cell DGR of ST36 area in L + EA, DL + ZEA and XL + ZEA groups were comparable to that of EA group (P>0.05), and such was the case in MA-related groups.
Conclusion: After nerve block of the local and proximal acupoints rather than the distal acupoint innervated by the same nerve, the analgesic effect of both MA and EA of ST36 is obviously attenuated; but no marked influences on MA- and EA-induced mast cell degranulation are found.