Motion-Style Scalp Acupuncture Ameliorates Post-Stroke Muscle Spasticity Through Cerebral Blood Flow Augmentation and 5-HT2AR-Mediated Spinal KCC2 Reactivation.

BACKGROUND: Muscle spasticity, a prevalent and debilitating motor impairment after stroke, severely compromises patients' functional recovery and quality of life. Motion-style scalp acupuncture (MSSA), a novel integrative therapy combining scalp acupuncture (SA) with targeted exercise training, has emerged as a promising strategy for post-stroke spasticity (PSS). This study investigated the mechanisms underlying MSSA's therapeutic effects, focusing on 5-HT2AR-mediated KCC2 reactivation in spinal motoneurons. METHODS: Using a rat model of permanent middle cerebral artery (MCA) occlusion, we evaluated MSSA's effects through behavioral assessments (Zea Longa, modified Ashworth scale (MAS), screen test), cerebral blood flow (laser speckle imaging), and infarct area analysis (TTC staining). Spinal reflex excitability was quantified via H-reflex electrophysiological recordings, while molecular mechanisms were examined using Western blot, RT-qPCR, and double immunofluorescence labeling. RESULTS: Our results demonstrated that MSSA significantly improved neurological function, reduced muscle tone, and attenuated spinal hyperreflexia. These improvements were associated with enhanced cerebral blood flow and reduced infarct areas. Furthermore, MSSA significantly upregulated the expression of 5-HT2AR and KCC2 in the spinal cord. Pharmacological validation using a 5-HT2AR antagonist and agonist confirmed the crucial role of 5-HT2AR in mediating MSSA's therapeutic effects. CONCLUSION: These findings demonstrate that MSSA ameliorates PSS through dual mechanisms: improving cerebral blood flow to the ischemic penumbra and restoring spinal inhibitory control via 5-HT2AR-dependent KCC2 reactivation. This study not only elucidates the mechanisms of MSSA but also provides a novel therapeutic strategy for PSS management.