Zhao Jiang, Lu Qudong, Yang Zhengxin, Sun Bishao, Zhu Jingzheng, Zhang Hengshuai, Yang Chengfei, Yi Shanghong, Dong Xinyou
Department of Urology, Second Affiliated Hospital, Army Military Medical University, Chongqing, 400037, China.
Department of Urology, People's Hospital of Shapingba District, Chongqing, 400030, China.
Int Urogynecol J. 2023 Apr;34(4):843-851. doi: 10.1007/s00192-022-05224-3. Epub 2022 Jun 11.
Genome-wide association studies suggest that autophagy plays an important regulatory role in inflammatory and autoimmune diseases. Inflammation and immune regulation disorders are involved in the occurrence and development of interstitial cystitis/bladder pain syndrome (IC/BPS). However, the changes and roles of autophagy in IC/BPS have not been reported. Therefore, this study aimed to investigate bladder autophagy and inflammation changes in patients with IC/BPS.
Bladder specimens (n = 5) from patients with cystectomy due to end-stage IC/BPS were collected. The bladder samples of the control group (n = 5) were derived from the normal area bladder tissue after radical cystectomy. H&E and toluidine blue staining were used for histological evaluation. The co-location of LC3, alpha-smooth muscle actin (α-SMA), and autophagosome was investigated with double-labeled immunofluorescence and transmission electron microscopy (TEM). The expression of IL-6, TNF-α, Bax, caspase-3, and BCL-2 in the detrusor layer was analyzed using immunohistochemistry (IHC) and Western blot (WB).
Compared with the control group, bladder tissue from IC/BPS patients revealed thinner and edematous epithelium with many mast cells (P < 0.05) infiltrating into the muscle layer. By using TEM (P < 0.05), double-labeled immunofluorescence (P < 0.05), and Western blot (P < 0.05) in IC/BPS patients, autophagy was also found and was significantly increased in detrusor myocytes. IHC and WB indicate the expression of BCL-2 (P < 0.05) was decreased, while IL-6, TNF-α, Bax, and caspase-3 expression was elevated (P < 0.05).
The number of autophagosomes in detrusor cells was increased in IC/BPS. However, autophagy of detrusor muscle cells may not have sufficient phagocytic activity to effectively remove damaged proteins and mitochondria, which may lead to the continued deterioration of IC/BPS inflammation and apoptosis.
全基因组关联研究表明自噬在炎症和自身免疫性疾病中发挥重要调节作用。炎症和免疫调节紊乱参与了间质性膀胱炎/膀胱疼痛综合征（IC/BPS）的发生和发展。然而，自噬在IC/BPS中的变化及作用尚未见报道。因此，本研究旨在探讨IC/BPS患者膀胱自噬及炎症变化。
收集因终末期IC/BPS行膀胱切除术患者的膀胱标本（n = 5）。对照组（n = 5）的膀胱样本取自根治性膀胱切除术后正常区域的膀胱组织。采用苏木精-伊红（H&E）染色和甲苯胺蓝染色进行组织学评估。通过双标免疫荧光和透射电子显微镜（TEM）研究微管相关蛋白1轻链3（LC3）、α-平滑肌肌动蛋白（α-SMA）与自噬体的共定位。采用免疫组织化学（IHC）和蛋白质免疫印迹法（WB）分析逼尿肌层中白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）、凋亡蛋白Bax、半胱天冬酶-3（caspase-3）和凋亡蛋白B细胞淋巴瘤-2（BCL-2）的表达。
与对照组相比，IC/BPS患者的膀胱组织显示上皮变薄且水肿，有许多肥大细胞浸润至肌层（P < 0.05）。通过对IC/BPS患者使用TEM（P < 0.05）、双标免疫荧光（P < 0.05）和WB（P < 0.05），发现自噬现象，且在逼尿肌细胞中显著增加。IHC和WB表明BCL-2的表达降低（P < 0.05），而IL-6、TNF-α、Bax和caspase-3的表达升高（P < 0.05）。
IC/BPS患者逼尿肌细胞中自噬体数量增加。然而，逼尿肌细胞的自噬可能没有足够的吞噬活性来有效清除受损蛋白质和线粒体，这可能导致IC/BPS炎症和凋亡持续恶化。
