放射性膀胱炎（RC）是盆腔癌放疗后一种复杂而常见的并发症。艾卡瑞苷 II (ICAII) 是从中药淫羊藿中提取的黄酮类化合物，具有多种药理活性。本研究旨在探讨ICAII对RC大鼠的膀胱保护作用及其可能机制。采用盆腔X线照射诱导放射性膀胱炎大鼠模型，通过膀胱容量和膀胱功能评估膀胱功能。 ICAII 处理后的泄漏点压力 (LPP)。 HE和Masson染色用于评估膀胱的组织病理学变化。通过ELISA测定IL-6、TNF-α、IL-10、IL-4和IL-1β以评估炎症水平。通过转录组测序观察ICAII处理的RC基因水平的变化，然后通过差异表达基因的PPI、GO和KEGG富集分析探索潜在的作用靶点和生物学机制。最后，使用免疫组织化学、RT-qPCR、分子对接和 CETSA 等方法对预测的作用靶点进行了实验验证。ICAII 显着增加了膀胱体积和 LPP，改善了膀胱组织的病理损伤，降低了 IL-6、TNF-α、和 IL-1β，并增加辐射损伤大鼠中 IL-10 和 IL-4 的水平。通过转录组测序共获得90个差异表达基因，PPI分析确定H3F3C、ISG15、SPP1和LCN2为可能的潜在作用靶点。 GO和KEGG分析显示，这些差异表达基因主要富集在细胞色素P450异生物质代谢、花生四烯酸代谢、金黄色葡萄球菌感染和化学致癌-活性氧等途径中。实验验证表明ICAII能够显着增加H3F3C和ISG15的表达并抑制SPP1和LCN2的表达。 ICAII 与 H3F3C、ISG15、SPP1 和 LCN2 结合良好，其中与 H3F3C 的结合能力最好。此外，ICAII还能抑制膀胱上皮细胞内H3F3C的蛋白降解。ICAII可能通过调节H3F3C、ISG15、SPP1、LCN2靶点减轻膀胱炎症反应，抑制膀胱组织纤维化过程，对膀胱具有保护作用放射损伤的老鼠。特别是，H3F3C可能是最有前途的治疗靶点之一。

Radiation cystitis (RC) is a complex and common complication after radiotherapy for pelvic cancer. Icariside II (ICAII) is a flavonoid compound extracted from Epimedium, a traditional Chinese medicine, with various pharmacological activities. The aim of the present study was to investigate the cysto-protective effects of ICAII in RC rats and its possible mechanisms.A rat model of induced radiation cystitis using pelvic X-ray irradiation was used, and bladder function was assessed by bladder volume and bladder leakage point pressure (LPP) after ICAII treatment. HE and Masson stains were used to assess the histopathological changes in the bladder. IL-6, TNF-α, IL-10, IL-4 and IL-1β were measured by ELISA to assess the level of inflammation. The gene-level changes in ICAII-treated RC were observed by transcriptome sequencing, and then the potential targets of action and biological mechanisms were explored by PPI, GO and KEGG enrichment analysis of the differentially expressed genes. Finally, the predicted targets of action were experimentally validated using immunohistochemistry, RT-qPCR, molecular docking and CETSA.ICAII significantly increased bladder volume and the LPP, ameliorated pathological damage to bladder tissues, decreased the levels of IL-6, TNF-α, and IL-1β, and increased the levels of IL-10 and IL-4 in radiation-injured rats. A total of 90 differentially expressed genes were obtained by transcriptome sequencing, and PPI analysis identified H3F3C, ISG15, SPP1, and LCN2 as possible potential targets of action. GO and KEGG analyses revealed that these differentially expressed genes were mainly enriched in the pathways metabolism of xenobiotics by cytochrome P450, arachidonic acid metabolism, Staphylococcus aureus infection and chemical carcinogenesis - reactive oxygen species. Experimental validation showed that ICAII could significantly increase the expression of H3F3C and ISG15 and inhibit the expression of SPP1 and LCN2. ICAII binds well to H3F3C, ISG15, SPP1 and LCN2, with the best binding ability to H3F3C. Furthermore, ICAII inhibited the protein degradation of H3F3C in bladder epithelial cells.ICAII may alleviate the bladder inflammatory response and inhibit the fibrosis process of bladder tissues through the regulation of H3F3C, ISG15, SPP1, and LCN2 targets and has a protective effect on the bladder of radioinjured rats. In particular, H3F3C may be one of the most promising therapeutic targets.