Objectives: To investigate the therapeutic efficacy and mechanism of pentosan polysulfate (PPS) for cyclophosphamide (CYP)-induced interstitial cystitis/bladder pain syndrome (IC/BPS) in mice.
Methods: Female C57BL/6 mice (6-8 weeks old) were randomized into control group, PPS treatment (25 mg/kg via gavage for 3 weeks) group, CYP treatment (3 separate intraperitoneal injections at 50 mg/kg in week 4), and CYP+PPS treatment group. Gut microbiota alterations of the mice were analyzed using 16S rDNA sequencing and non-targeted metabolomics. Fecal microbiota transplantation (FMT) was performed in CYP-treated recipient mice and those treated with both CYP and PPS. In the in vitro experiment, LPS-stimulated human bladder epithelial cells (SV-HUC-1) were used to assess the effects of deoxycholic acid (DCA) and TGR5 signaling inhibitor SBI-115 on barrier functions of bladder epithelial cells.
Results: PPS treatment significantly improved the mechanical pain thresholds, restored the urodynamic parameters, and attenuated bladder inflammation and barrier dysfunction in CYP-treated mice. Mechanistically, PPS enriched the abundance of Eubacterium xylanophilum and increased DCA levels in the intestines of CYP-treated mice. FMT experiments confirmed microbiota-dependent therapeutic effects of PPS, shown by reduced bladder pathology in the recipient mice treated with both CYP and PPS. In SV-HUC-1 cells, DCA obviously alleviated LPS-induced inflammation and barrier disruption, and treatment with SBI-115 abolished these protective effects of DCA.
Conclusions: PPS ameliorates IC/BPS in mice by remodeling gut microbiota to enhance DCA production and activate TGR5 signaling, suggesting a novel microbiota-bile acid-TGR5 axis that mediates the therapeutic effect of PPS and a therapeutic strategy for IC/BPS by targeting gut-bladder crosstalk.
目的: 探究多硫酸戊聚糖（PPS）通过调节肠道微生物群和胆汁酸代谢来缓解环磷酰胺（CYP）诱导的间质性膀胱炎/膀胱疼痛综合征（IC/BPS）小鼠模型的疗效及其潜在机制。方法: 通过随机化方法将6~8周龄雌性C57BL/6小鼠分为：对照组、PPS处理组（PPS组）、CYP诱导组（CYP组）和CYP+PPS联合处理组（C+P组），6只/组。PPS以25 mg/kg剂量连续3周灌胃处理，CYP以50 mg/kg剂量在第4周分3次腹腔注射以建立IC/BPS模型。采用16S rDNA测序及非靶向代谢组学分析肠道菌群与代谢产物变化；通过粪便微生物移植（FMT）实验（CYP-FMT与C+P-FMT受体组）验证菌群介导作用。体外以LPS诱导人膀胱上皮细胞（SV-HUC-1）炎症模型，分组探究脱氧胆酸（DCA）及TGR5抑制剂（SBI-115）对屏障功能的影响。结果: PPS治疗提升了CYP诱导的IC/BPS小鼠模型的机械疼痛阈值，改善了尿动力学参数，并减轻了膀胱炎症及屏障损伤（P<0.05）。PPS通过增加肠道中嗜木聚糖真杆菌的丰度和促进DCA产生，调节了肠道菌群和胆汁酸代谢（P<0.05）。FMT实验证实了PPS的疗效依赖于肠道菌群。在细胞层面，DCA激活TGR5受体，减轻了LPS诱导的SV-HUC-1细胞炎症和屏障损伤（P<0.05）。结论: PPS通过富集嗜木聚糖真杆菌菌群促进DCA生成，激活TGR5信号通路，从而减轻膀胱炎症并修复屏障功能。本研究首次揭示PPS通过菌群-胆汁酸-TGR5轴调控IC/BPS的新机制，为靶向肠道微生态治疗膀胱疾病提供理论依据。.
Keywords: bile acids; cyclophosphamide; gut microbiota; interstitial cystitis/bladder pain syndrome; pentosan polysulfate.