Objective To investigate the therapeutic effects of Lactiplantibacillus plantarum HG20 on collagen induced arthritis (CIA) rats and its mechanism.

Methods The CIA rats were constructed by injecting bovine type Ⅱ collagen, and the effects of HG20 treatment on arthritis score, ankle swelling degree and pathological changes of knee joint were observed. The effects of HG20 treatment on the serum levels of cytokines, and inflammatory and apoptotic pathways of splenocytes in rats were analyzed.

Results Compared with the model group, HG20 reduced the degree of joint swelling and ankle swelling, improved the bone destruction, synovial hyperplasia and inflammatory cell infiltration, and decreased the levels of pro-inflammatory cytokinesinterleukin (IL)-6, IL-17, tumor necrosis factor -α (TNF-α), IL-1β and IL-23 (P ＜ 0.05). The expression of pro-inflammatory cytokines was down-regulated through the nuclear factor-κB (NF-κB) pathway, and splenocyte apoptosis was inhibited by suppressing the IL-23/IL-17 pathway and regulating the apoptotic pathway.

Conclusions HG20 has adjuvant therapeutic effect on arthritis in CIA rats, and its mechanism may be related to the inhibition of IL-23/IL-17 pathway.