Piezo2 in sensory neurons contributes to inflammation-induced bladder overactivity and is associated with the effects of electroacupuncture.

OBJECTIVES: To assess the effects of varying doses of cyclophosphamide (CYP) on lower urinary tract function in rats, and to further investigate the role of Piezo2 in sensory neurons in a CYP-induced interstitial cystitis/bladder pain syndrome (IC/BPS) model and its potential as a therapeutic target for electroacupuncture (EA). METHODS: Lower urinary tract function was assessed by employing cystometry, external urethral sphincter electromyography, and void spot assay. Bladders were harvested for histological observation. L6-S1 dorsal root ganglia were collected for detection of Piezo2 expression by RNAscope, immunofluorescence staining, and Western blotting. L6-S1 spinal cords were harvested for c-Fos immunofluorescence staining to evaluate activation of spinal neurons. RESULTS: Five days subsequent to the completion of administration with 50, 60, and 75 mg/kg CYP, bladder function in rats still had not returned to baseline levels. However, the 40 mg/kg dose only caused a reduction in the area under the curve of pressure traces, indicating a change in bladder contractility. Administration with 75 mg/kg CYP did not induce a more severe bladder phenotype than 60 mg/kg CYP. Intrathecal injection of antisense oligonucleotides to knockdown Piezo2 expression in sensory neurons ameliorated bladder overactivity and urethral hyperreflexia in rats with CYP-induced IC/BPS, accompanied by lessened activation of spinal neurons. Aside from that, EA improves lower urinary tract function in rats with cystitis, which may be associated with the downregulation of Piezo2 expression in sensory neurons and the lessened activation of spinal neurons. CONCLUSION: Piezo2 in sensory neurons contributes to inflammation-induced bladder overactivity and is associated with the effects of EA. Collectively, targeted inhibition of Piezo2 expression and function may represent a promising novel strategy for managing inflammatory bladder dysfunction, with these data also shedding preliminary light on how EA exerts its therapeutic effects in this condition. On top of that, our study provides novel insights into the characteristics of the CYP-induced IC/BPS model and the establishment of a rat void spot assay protocol.