Suoquan Wan mitigates bladder overactivity via modulation of neuroimmune homeostasis in perimenopausal rats.

Background: Overactive bladder (OAB) is a common disorder in perimenopausal women, involving detrusor regulation by bladder neuro-immune interactions. While Suoquan Wan (SQW) has shown efficacy in alleviating OAB symptoms, its underlying mechanisms remain unclear.

Purpose: The aim of this study was to investigate the therapeutic effects of SQW on perimenopausal overactive bladder (OAB) and elucidate its underlying mechanisms in restoring bladder neuro-immune homeostasis.

Methods: Initially, vaginal smears were performed to identify perimenopausal rats. The effects of SQW on the structure and function of the perimenopausal bladder were assessed using urodynamic studies, organ bath assays, and histological analyses, including hematoxylin and eosin (HE) and Masson staining. Subsequently, single-nucleus RNA sequencing (snRNA-seq) was conducted to investigate the mechanisms by which SQW modulates neuron-macrophage interactions. To validate the sequencing data, PCR and immunofluorescence (IF) assays were utilized to evaluate neural homeostasis. Further analyses involved IF, flow cytometry, and fluorescence bead assays to determine the function and proportion of bladder macrophages. The co-localization of neurons and macrophages was visualized using IF. Finally, transwell co-culture experiments were carried out to explore the regulatory effects of SQW on bladder neuro-immune homeostasis.

Results: SQW significantly attenuates the frequency of non-micturition contractions and reduces residual urine volume, alleviates detrusor hyperactivity in OAB rats in response to external stimuli such as EFS, CCh, and KCl, and markedly improves urinary efficiency in perimenopausal OAB rats. SnRNA-seq data indicate that SQW modulates bladder neuro-immune homeostasis in these rats. Furthermore, SQW obviously decreases the proportion of ChAT-positive nerve fibers while enhancing the abundance of nNOS and MAP-positive nerve fibers in the bladder. SQW also reduces the proportion of CD45 CD11b/CMHCⅡ macrophages in the bladder muscle layer. Transwell co-culture assays reveal that the effects of SQW on MAP-2 and ChAT are mediated through the neuron-macrophage interaction mechanism.

Conclusions: SQW alleviated perimenopausal OAB by specifically modulating the neuron-macrophage interaction and enhancing bladder neuro-immune homeostasis.