Mechanism of electroacupuncture treating detrusor-bladder neck dyssynergia after suprasacral spinal cord injury by proteomics

Objectives

To elucidate the potential mechanisms of electroacupuncture (EA) in restoring detrusor-bladder neck dyssynergia (DBND) following suprasacral spinal cord injury (SSCI).

Methods

A total of 52 specific pathogen-free (SPF) grade famale Sprague-Dawley (SD) rats (10 – 12 weeks, 250 – 280 g) were randomly assigned to either a sham group (n = 12) or a spinal cord injury model group (n = 40). In the model group, DBND was induced through Hassan Shaker spinal cord transection at T10 level, with 24 rats meeting inclusion criteria and subsequently randomized into DBND group (n = 12) and EA intervention group (DBND + EA group, n = 12). After spinal shock recovery (day 19 after modeling), DBND + EA group received EA treatment at Ciliao (BL32), Zhongji (RN3), and Sanyinjiao (SP6) acupoints for 20 min per session at 10/50 Hz frequencies, once daily for 10 d. Sham and DBND groups received anesthesia only without EA intervention. On day 29 post-modeling, all rats underwent urodynamic assessments, followed by hematoxylin and eosin (HE) staining, tandem mass tag (TMT) proteomics, and Western blot (WB) analysis of detrusor and bladder neck tissues. Differentially expressed proteins (DEPs) were defined as proteins with P < 0.05, unique peptides ≥ 2, and fold change > 1.2 or < 0.83. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed using KOBAS 3.0 (P < 0.01), and protein-protein interaction (PPI) networks were analyzed using Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) 11.5 and Cytoscape 3.9.1.

Results

Compared with sham group, DBND group showed significantly elevated leak point pressure (LPP) and maximum cystometric capacity (MCC) (both P < 0.01). EA treatment significantly reduced both LPP and MCC compared with DBND group (P < 0.01 and P < 0.05, respectively). HE staining revealed that EA reduced detrusor fibrosis and improved bladder neck inflammation. TMT proteomics identified 30 overlapping DEPs in detrusor and 59 overlapping DEPs in bladder neck when comparing DBND + EA/DBND groups with sham group. In detrusor tissue, KEGG analysis revealed 10 significantly enriched pathways (P < 0.01), including mitogen-activated protein kinase (MAPK) signaling pathway. PPI analysis showed 22 of 30 DEPs were interconnected. In bladder neck tissue, 14 pathways were significantly enriched (P < 0.01), including relaxin signaling pathway, with 51 of 59 DEPs showing interconnections. Both TMT and WB validations demonstrated that compared with sham controls, DBND rats exhibited upregulated collagen type IV alpha 2 chain (Col4a2) and downregulated guanine nucleotide-binding protein G(z) subunit alpha (Gnaz) in detrusor tissue, while EA treatment normalized both proteins (both P < 0.05). In bladder neck tissue, DBND rats showed decreased expression of smoothelin (Smtn) and calcium-activated potassium channel subunit beta-1 (Kcnmb1) compared with sham controls (both P < 0.01), which were both upregulated following EA treatment (P < 0.01 and P < 0.05, respectively).

Conclusion

EA restores detrusor-bladder neck coordination in DBND through dual-target mechanisms. In detrusor tissue, EA modulates contraction via extracellular matrix remodeling, cyclic adenosine monophosphate (cAMP) signaling pathway regulation, and enhanced adenosine triphosphate (ATP) biosynthesis mediated by neurotransmitters. In bladder neck tissue, EA promotes relaxation by maintaining contractile phenotypes, reducing fibrosis, suppressing smooth muscle excitation, and regulating presynaptic neurotransmitter release. These findings provide mechanistic insights into EA's therapeutic role in managing DBND.