Joss-stick moxibustion reduces inflammatory response of acute eczema by inhibiting IL-6/STAT3 signaling, and balancing Th17/Treg to normalize filaggrin and Caspase-14 levels in rats

To investigate the effect of joss-stick moxibustion on the balance of helper T cell 17 (Th17)/regulatory T cell (Treg) through interleukin-6 (IL-6)/signal transduction and transcriptional activator 3 (STAT3) pathway in acute eczema (AE) rats.

A total of 24 male SD rats were randomly divided into blank control, AE model, boric acid solution (BAS) washing, and moxibustion groups, with 6 rats in each group. The AE model was established by external application of 7% dinitrochlorobenzene (DNCB, 100 μL) to the abdominal skin once for the first day, 3 days later, the 5% DNCB to the right back sin, every three days for 3 times. Rats of the blank control group received external application of distilled water at the skin and those of the BAS washing group received external application of 3% BAS solution wet packing. Rats of the moxibustion group received local heat stimulation of joss-stick moxibustion at the injured skin locus for 30 min, once a day, 5 days a week, for 2 weeks. At the end of the experiments, the injured skin (on the right side of the back) and the healthy skin on the left side of the back were sampled using a round puncher (6 mm in diameter) for calculating the skin swelling degree. The inhibition rate equals to the skin swelling degree/weight of the healthy skin×100%. The content of serum IL-6 was detected using ELISA, the expression levels of STAT3 and ROR-γt mRNAs in the injured skin tissue were detected using real-time fluorescence quantitative PCR, and the expression levels of p-STAT3, ROR-γt, and Foxp3 protein were detected using Western blot. The immunoactivities of filaggrin (FLG) and Caspase-14 in the injured skin tissue were detected by immunohistochemistry.

Compared with the blank control group, the topical skin swelling degree, inhibition rate, serum IL-6 content, expression levels of STAT3 and ROR-γt mRNAs, and p-STAT3, ROR-γt protein expression levels were significantly increased (P<0.01, P<0.05), while the expression level of Foxp3 protein and the immunoactivities of FLG and Caspase-14 were markedly down-regulated (P<0.01) in the model group. In comparison with the model group, both the increase and decrease of the aforementioned 10 indexes after the modeling were reversed in the BAS washing and moxibustion groups (P<0.01, P<0.05). No significant differences were found between the BAS washing and moxibustion groups in the abovementioned 10 indexes.

Joss-stick moxibustion can reduce the inflammatory response in AE rats, which may be related to its functions in suppressing the overexpression of IL-6/STAT3 signaling pathway to promote the restoration of Th17/Treg balance, thus normalizing the levels of FLG and Caspase-14.