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.

本研究旨在通过病理分析及肿瘤坏死因子-α（tumor necrosis factor-alpha, TNF-α）、白细胞介素-18（interleukin-18, IL-18）水平检测，探讨乳酸菌发酵提取物（lactic acid bacterial fermentation extract, LABEF）对大肠杆菌脂多糖（Escherichia coli lipopolysaccharide, LPS）诱导的小鼠膀胱膀胱炎的干预作用。实验小鼠以5 μg/L的剂量口服给予LABEF，连续给药10天后，实验组（n = 12）经膀胱内灌注5 μg/L LPS。24小时后采集膀胱组织，进行苏木精-伊红（hematoxylin and eosin, H-E）染色，并采用半定量评分法评估炎症程度（膀胱炎症指数, BII）。同时开展TNF-α免疫组化染色及多重细胞因子检测，以测定TNF-α与IL-18的表达水平，并与对照组（n = 12）的结果进行对比。对照组与实验组的BII分别为2.7 ± 0.5和1.1 ± 0.7，两组评分存在显著统计学差异（p < 0.001）。TNF-α免疫组化染色结果亦呈现相同趋势。多重细胞因子检测结果显示，对照组与实验组的TNF-α水平分别为2.82 ± 1.35 pg/mg和1.55 ± 0.56 pg/mg，组间差异具有统计学意义（p = 0.007）。综上，口服给予LABEF可对小鼠膀胱内灌注LPS诱导的炎症反应及TNF-α表达起到预防作用。未来仍需开展进一步研究以明确该发现的临床应用价值。