Preventive effect of Lactobacillus mixture on inflammation and cytokines in lipopolysaccharide-induced cystitis in mice

This study aimed to investigate the effects of lactic acid bacterial fermentation extract (LABEF) on cystitis induced by <i>Escherichia coli</i> lipopolysaccharide (LPS) in the mouse bladder by pathological analyses and measurement of the levels of tumor necrosis factor-alpha (TNF-α) and interleukin-18 (IL-18). LABEF was administered orally (5 μg/L) to mice for 10 days following which, the study group (n = 12) was injected intravesically with 5 μg/L LPS. The bladder tissue was then harvested after 24 hours and subjected to hematoxylin and eosin (H-E) staining. A semiquantative score was used to evaluate inflammation (bladder inflammation index; BII). TNF-α immunohistochemical staining and multiplex cytokine assay were also performed. TNF-α and IL-18 levels were determined. The results were compared with those of the control group (n = 12). The BII in the control and study groups was 2.7 ± 0.5 and 1.1 ± 0.7, respectively, with the control group scores significantly differing from the study group scores (p value &lt; 0.001). TNF-α immunohistochemical staining showed similar results. The TNF-α levels determined by the multiplex cytokine assay were 2.82 ± 1.35 pg/mg and 1.55 ± 0.56 pg/mg for the control and study groups, respectively, and the difference in values between these groups was statistically significant (p value = 0.007). Thus, oral administration of LABEF appears to have a preventive effect against the inflammatory responses and TNF-α expression induced by intravesical instillation of LPS in the mouse bladder. Further studies are required to determine the clinical application of this finding.