Probiotic potential of Lactobacillus isolated from horses and its therapeutic effect on DSS-induced colitis in mice.

This research aims to discover the potential therapeutic benefits of Lactobacillus, particularly its strain Lactobacillus plantarum A3, isolated from horses on Inflammatory Bowel Disease (IBD) observed in a Dextran sulfate sodium salt induced colitis mouse model.

Study Objectives and Background

• The research stemmed from the observation that IBD is a challenging disease affecting both humans and animals, often resistant to treatment.
• Lactobacillus, `a bacteria with possible probiotic characteristics, has been utilized to treat various diseases in animals.
• The study aimed to explore this bacteria, specifically strains of Lactobacillus isolated from horses, to evaluate its effects on an IBD model in mice.
• Horses, as hindgut fermentation animals, have an abundance of gut microflora, including various strains of Lactobacillus. However, detailed data on these microbes and their potential uses are limited.

Methods and Results

• The researchers isolated four isolates of Lactobacillus from the feces of healthy adult male horses and analyzed their biological characteristics.
• The resultant isolates named A2.5, A7.1, A3 and B8.2 were identified as Pediococcus pentosaceus, Lactobacillus plantarum, and Weissella cibaria respectively.
• It was documented that all four isolates demonstrated tolerance to acidic environments, bile salt concentrations and artificial gastrointestinal fluid, indicating potential viability in the harsh conditions of the gut.
• Further evaluations showed Lactobacillus plantarum A3 (specified as A3 in the paper) displayed a high self-aggregation rate and hydrophobicity, along with an adhesion rate of approximately 28.85%.
• None of the isolates were hemolytic, and they showed sensitivity to commonly used antibiotics.
• The bacteria isolates also showed promising antibacterial and antioxidant activities. Furthermore, these isolates were found to regulate lipid A-like molecules, lipopolysaccharides (LPS) -stimulated Caco-2 cells which are common model cells for research on the intestine.
• After this evaluation, Lactobacillus plantarum A3 was selected for further studies. The researchers used this strain to treat mice induced with colitis through the administration of Dextran sulfate sodium salt (DSS).
• Compared to the control group, mice treated by Lactobacillus plantarum A3 showed significant improvements in their Disease activity index (DAI), colon length, and pathological scores. They also exhibited a regulated cytokine secretion at the gene expression level, thus indicating reduced inflammation.

Conclusions and Implications

• This research successfully isolated and identified potentially beneficial strains of Lactobacillus from the feces of healthy horses.
• Among these, Lactobacillus plantarum A3 showed promising effects on IBD in a mouse model.
• This study thus provides early evidence that Lactobacillus plantarum A3 might be used as a potential treatment for IBD in the future. However, further studies in more complex models will be needed to confirm these results.