Postmenopausal women with ovarian hormone deficiency (OHD) often experience urological dysfunctions such as overactive bladder (OAB), stress urinary incontinence (SUI), and recurrent urinary tract infections (UTI). Previous studies have suggested a link between estrogen deficiency and impaired bladder function, with autophagy playing a crucial role in maintaining bladder homeostasis. However, the underlying molecular mechanisms remain unclear.

Female Sprague-Dawley rats were divided into three groups: (1) The Sham group, (2) The OVX group, and (3) The OVX + Estradiol (E2) group. Serum estradiol levels, bladder function, and molecular markers of autophagy were analyzed. Bladder urodynamics was assessed using cystometrogram studies and tracing voiding behavior. Detrusor contractility was assessed using bladder muscle strips. Transmission electron microscopy (TEM) was employed to examine bladder ultrastructure. We used data-based quantitative proteomics by liquid chromatography-mass spectrometry (LC-MS) and bioinformatics analysis. Construction of the miRNA 200 family library for next-generation sequencing and the expression of miRNA-200 family was examined using real-time quantitative PCR (RT-qPCR). The expressions of transcription factor (KLF4) and autophagy-related proteins (mTOR, ATG7, ATG12, Beclin-1, VPS34 and LC3 I/II) were examined using Western blotting.

The OVX treated rats exhibited significant bladder dysfunction with an increase in micturition frequency, deteriorated micturition volume and reduced bladder contractile response, while E2 treatment effectively restored serum estradiol levels and improved the bladder contractility. Moreover, the OVX group exhibited significantly the upregulation of miRNA-200b, which suppressed KLF4, leading to autophagy inhibition, as evidenced by increased p-mTOR expression and decreased levels of ATG7, ATG12, Beclin-1, VPS34 and LC3 I/II. However, the OVX + E2 group downregulated miRNA-200b, restored KLF4 expression and enhanced autophagy by decreasing p-mTOR expression as well as increasing the levels of ATG7, ATG12, VPS34 and LC3 I/II to improve OAB. Therefore, estradiol therapy may serve as a potential intervention for postmenopausal women experiencing OAB.

These findings suggested that estradiol treatment enhanced bladder autophagy via the miRNA-200b / KLF4 / mTOR pathway, thereby mitigating OAB symptoms in OHD - induced OAB rats.