To investigate effects moxibustion exerts on A20 expression and regulation of intestinal epithelial tight junctions via the TNF-α-NF-κB-MLCK pathway in Crohn's disease (CD).

C57BL/6 wild type (WT) and A20^IEC−KO mice (48 each) were randomly divided into normal control (NC), model control (MC), mesalazine (MESA) and herbs-partitioned moxibustion (HPM) groups (12 mice per group). An experimental model of CD was established using 2, 4, 6 trinitrobenzene sulfonic acid. MESA and HPM mice were treated with MESA and HPM (at Tianshu (ST25) and Qihai (CV6)), respectively. In HPM group, moxa cones (0.5 cm in diameter and 0.3 cm in height) made of refined mugwort floss were placed on herbal cakes (medicinal formula dispensing [radix] Aconiti praeparata, [cortex] Cinnamomi, etc.) at Tianshu (ST25) and Qihai (CV6) and ignited. The moxa cones were ignited, and two moxa cones were used for each treatment once daily for 10 days. In MESA group, mice were fed MESA, which was prepared at a proportion of 1:0.0026, twice daily for 10 days.

Intestinal epithelial ultrastructure of WT HPM mice improved more than A20^IEC−KO HPM mice compared to MC mice. WT HPM mice exhibited greater expression of A20 compared with MC mice (P < 0.01). TNF-α, NF-kB p65, MLCK, MLC, TRAF6 and RIP1 levels in A20^IEC−KO and WT HPM mice were all decreased compared to MC mice (P_all < 0.01). NF-κB p65、MLCK and TRAF6 levels were increased in A20^IEC−KO HPM mice as compared to WT HPM mice (P_all < 0.05). Intestinal epithelial levels of occludin, claudin-1, ZO-1 and F-actin increased in all HPM mice (P_all  < 0.01–0.05), while occludin, claudin-1, and ZO-1 levels were lower in A20 ^IEC-KO HPM mice (P < 0.05, P < 0.01, P < 0.01).

HPM downregulates abnormal activation of the TNF-α-NF-κB-MLCK pathway by upregulating expression of A20 in a mouse model of CD, thereby protecting intestinal epithelial tight junctions and repairing the damage CD causes to the intestinal epithelial barrier.