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Effects of lysed Enterococcus faecalis FK-23 on experimental allergic rhinitis in a murine model
Luping Zhu1, Takashi Shimada, Ruoxi Chen
1Department of Otorhinolaryngology, the First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China;
Abstract:
In the current study, we sought to investigate whether lysed Enterococcus faecalis FK-23 (LFK), a heat-killed probiotic preparation, attenuated eosinophil influx into the upper airway and had immunomodulatory activity in a murine allergic rhinitis model. Eighteen BALB/c mice were divided into three groups; the ovalbumin (OVA)-sensitized/challenged group, which received saline orally for 6 weeks (OVA group), the OVA-sensitized/challenged group, which received LFK orally for 6 weeks (LFK-fed group), and the non-sensitized group, which received saline for 6 weeks (saline control group). Nasal rubbing and sneezing were monitored during the study. After the final challenge, interleukin (IL)-4, interferon (IFN)-γ, and OVA-specific IgE levels in the sera and splenocyte culture supernatants were determined, eosinophilic infiltrate into the upper airway was quantified, and splenic CD4+CD25+ regulatory T cells (Tregs) were examined by flow cytometry. We found that nasal rubbing was significantly reduced in LFK-fed mice compared to the OVA group on d 27 and 35, and sneezing was significantly inhibited by LFK administration for 35 d. LFK-fed mice had significantly less eosinophil influx into the nasal mucosa than the OVA group. There were no significant differences between the LFK-fed group and OVA group in the serum and splenocyte culture supernatant levels of IL-4, IFN-γ, and OVA-specific IgE. Interestingly, the LFK-fed mice had a significantly greater percentage of splenic CD4+CD25+ Tregs than OVA group. Our results indicate that oral administration of LFK may alleviate nasal symptoms, reduce nasal eosinophilia, and increase the percentage of CD4+CD25+ Tregs in experimental allergic rhinitis.
Insights
Lysis Enterococcus faecalis FK-23 (LFK) reduced allergic rhinitis symptoms in mice by decreasing eosinophil influx and increasing regulatory T cells (Tregs). This heat-killed probiotic shows potential for managing upper airway inflammation.
Area of Science:
- Immunology
- Microbiology
- Allergy Research
Background:
- Allergic rhinitis is characterized by upper airway inflammation with eosinophil infiltration.
- Probiotic interventions are explored for their immunomodulatory effects in allergic diseases.
- Enterococcus faecalis FK-23 (LFK) is a heat-killed probiotic preparation.
Purpose of the Study:
- To investigate the efficacy of LFK in an experimental murine model of allergic rhinitis.
- To determine if LFK attenuates eosinophil influx into the upper airway.
- To assess the immunomodulatory activity of LFK, specifically its effect on regulatory T cells (Tregs).
Main Methods:
- BALB/c mice were sensitized and challenged with ovalbumin (OVA).
- Mice received either LFK or saline orally for six weeks.
- Nasal symptoms, eosinophil counts, cytokine levels (IL-4, IFN-γ), OVA-specific IgE, and splenic CD4+CD25+ Tregs were analyzed.
Main Results:
- LFK administration significantly reduced nasal rubbing and sneezing behaviors.
- LFK-fed mice exhibited significantly lower eosinophil infiltration in the nasal mucosa compared to controls.
- A significant increase in the percentage of splenic CD4+CD25+ Tregs was observed in LFK-fed mice.
- No significant differences in IL-4, IFN-γ, or OVA-specific IgE levels were found between groups.
Conclusions:
- Oral administration of LFK can alleviate nasal symptoms in experimental allergic rhinitis.
- LFK demonstrates potential in reducing eosinophilic inflammation in the upper airway.
- LFK may exert its beneficial effects by increasing the population of CD4+CD25+ regulatory T cells.
