Abstract: Objective    To observe the effect of the heat-treated and lysed Enterococcus faecalis FK-23 (LFK) on serum levels of IL-12 in a murine model of allergic rhinitis (AR), and to discuss the anti-allergic effect of LFK on experimental AR. Methods    A total of 75 BALB/c mice were divided into three groups: 1) positive control group, 2) LFK-treated group, and 3) negative control group. To establish the murine AR model, intraperitoneal injection and nasal drip with ovalbumin (OVA) were performed. Saline was used instead of OVA for negative control mice. Probiotic preparation of LFK was orally administrated in a process of 21 days (60mg/0.5mL/mouse per day) in LFK-treated mice. The positive and negative control mice received saline orally for 21 days. The IL-12 levels were quantified in serum using ELISA on day 22. Results    Serum levels of IL-12 were significantly decreased in the positive control group than those in the negative control group (P＜0.001), and significantly increased in the LFK-treated group than those in the positive control group (P＜0.001). However, serum levels of IL-12 were still significantly decreased in the LFK-treated group compared to the negative control group (P＜0.001). Conclusion    LFK, an Enterococcus probiotic preparation, has certain modulatory actions on cytokine IL-12, which might be related to its anti-allergic effect.

Key words: Cytokines, Mice, Rhinitis, allergic, Probiotics; , Interleukin-12