Nerve Block On The Point Of The Mast Cell Function And Acupuncture Analgesia Mechanism

Acupuncture analgesia has been verified to be an effective method and practiced clinically worldwide. Yet the mechanisms of acupuncture analgesia are still in exploration. It has been showed that nerves play a key role in the acupuncture analgesia mechanism both in central and peripheral aspect. And our previous studies showed that mast cell degranulation is positive correlation with acupuncture analgesia. And this study aimed to observe the effects of nerve block on manual-acupuncture (MA) and electro-acupuncture (EA) analgesia and mast cells degranulation in adjuvant arthritis rats in order to analyze the difference between the underlying peripheral mechanism of MA and EA analgesia.Methods: Arthritis model was established by injection of Freund's complete adjuvant (0.05ml) in the rat's right hind-paw after it had been deeply anesthetized with 10% chloral hydrate (40mg/kg). Zusanli (ST36) was chosen as the acupuncturing point. Eighty SD rats were randomized into control, model, normal+Lido (normal animals), EA, Lido+EA (injection of 2% Lidocaine hydrochloride 0.05ml and EA at Zusanli), DLido+ZEA (injection at Dubi (ST35) and EA at Zusanli), Xlido+ZEA (injection at Xiajuxu (ST39) and EA at Zusanli), MA, Lido+MA (injection and MA at Zusanli), Dlido+ZMA (injection at Dubi and MA at Zusanli) groups with 8 cases in each group. Paw Withdraw Latencies and mast cells degranulation ratios were recorded and computed as the analgesic effect or acupoints activation observation indicators. The electro-acupuncture was performed with dilatational wave, frequencies of 2/100 Hz and intensities of 0.5mA, 1mA, 1.5mA (each continuous 10 minutes). The manual-acupuncture was performed with needle of 25mm (injecting 7mm) by extracting and intercalating the needle for 30s, retaining the needle for 30s and then twisting and rotating the needle for 30s, retaining the needle for 30s. The alternation was repeated for continuous 20 minutes. Results:1. Compared with model group, the pain threshold (EA p<0.05, MA p<0.01) and mast cells degranulation ratios (both p<0.01) of EA and MA were significantly higher, which demonstrated both EA and MA have analgesia effect and mast cell degranulation is positive correlation with acupuncture analgesia.2 Compared with model group, the pain threshold and mast cells degranulation ratios mere injection of 2% Lidocaine hydrochloride (0.05ml) were not obviously affected (p>0.05).3 The analgesia effects of both MA and EA were obviously attenuated (p<0.01 vs EA) after nerve block by pretreated with Lidocaine hydrochloride at the acupuncturing point or at the acupiont of proximal end in the same neural stem while they were not by the same manipulations at the acupiont of distal end (p>0.05 vs EA). Degranulation ratios of mast cells caused by EA were not obviously affected by nerve block (p>0.05 vs EA).4 The analgesia effects of both MA and EA were obviously attenuated (p<0.01 vs MA) after nerve block by pretreated with Lidocaine hydrochloride at the acupuncturing point or at the acupiont of proximal end in the same neural stem. Degranulation ratios of mast cells caused by EA were not obviously affected by nerve block (p>0.05 vs MA).Conclusion: The effective signal of nerve conduction of MA analgesia is generated after the degranulation of mast cells in the process of acupoints activation or needle sense and it is the direct cause of generation of nerve signal. In the condition of EA, the acupoints activation is caused by the stimulation of electric signal on nerve receptor while the degranulation of mast cells is concomitant or feedback effect.