Anti-Inflammatory Effects of Moxibustion on Mice with Adjuvant Arthritis: Role of TRPV1

Aim and Objective: This research was done to observe the anti-inflammatory effect of moxibustion and explore the role of Transient Receptor Potential Vanilloid sub type 1 (TRPV1) on Mice with adjuvant arthritis. Method: Adjuvant arthritis (AA) was established by using the amount of 20 μL of Freund’s Adjuvant Complete (FCA) intradermal injected into right hindfoot plantar. 50 KM mice were randomized into 6 groups by random number table method: control group (n=10), model group (n=8), capsaicin group (n=8), capsazepine group (n=8), moxibustion group (n=8) and Moxibustion+Capsazepine (MC) group (n=8). 16 C57BL/6 wild-type mice are randomized into 2 groups by random number table method: Wild-Type (WT) model group and WT moxibustion group with 8 in each. 14 TRPV1 knockout mice are randomized into 2 groups by random number table method: knockout (KO) model group and KO moxibustion group with 7 in each. Each mouse in the capsaicin group is subcutaneously injected with the amount of 0.1 ml/10 g into the L5, L6 spinal cords. Each mouse in the capsazepine group was intraperitoneally injected with the amount of 0.1 ml/10 g. Similarly, each mouse in the moxibustion group, WT moxibustion group and KO moxibustion group was given a suspended moxibustion with 5 mm × 200 mm specially-made moxa stick for 20 minutes on L5 and L6 spinal cords. Kept the distance between the moxa stick and the skin where L5 and L6 spinal cords located was 10 ± 2 mm that the temperature was stabilized at 46 ± 1°C. Each mouse in MC group was intraperitoneally injected with the amount of 0.1 ml/10 g first, then after 15 minutes was given a suspended moxibustion for 20 minutes on L5 and L6 spinal cords. All the treatments above were performed at the same day when models were successfully establishedand performed once per day for 7 days in total. During the performance, mice in the control group, model group, WT model group and KO model group were of no treatment in any way. The right hindfoot paw volumes of mice in each group were measured and recorded on Day 1, Day 2, Day 4, Day 6 and Day 8 of the experiment. After all treatments, the serum IL-1β and TNF-α level was determined by ELISA. Results: Compared with the model group, the paw volumes in the moxibustion group was significantly decreased (P<0.01), simultaneously moxibustion caused a significant decrease in serum IL-1β and TNF-α levels (P<0.01). Compared with the model group, the paw volumes, serum IL-1β and TNF-α levels in the Moxibustion+Capsazepine (MC) group was significantly decreased (P<0.01); but compared with moxibustion group, the paw volumes, serum IL-1β and TNF-α levels in MC group was obviously increased with significance in between (P<0.05). Compared with KO control group, no changes in the paw volumes, serum IL-1β and TNF-α levels in KO moxibustion group, there was no significant difference in between (P>0.05). Conclusions: TRPV1 plays a central role in the anti-inflammatory effect of moxibustion, while the effect may be lost if lacked of TRPV1-mediated.