Harnessing theta-gamma coupled brainwaves using ultrasound for spinal astrocyte revitalization and sustained neuropathic pain relief in mice

Abstract

Ultrasound stimulation is a promising non-invasive strategy for neuropathic pain, yet its sustained effects and underlying mechanisms remain poorly understood. We investigated brainwave-patterned low-intensity continuous theta-burst ultrasound stimulation (LI-cTBUS) in a mouse model of partial sciatic nerve crush injury (PCI). LI-cTBUS substantially alleviated mechanical allodynia during and after treatment. Mechanistically, PCI upregulated brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) signaling, while LI-cTBUS enhanced extracellular BDNF uptake by spinal astrocytes, thereby normalizing the BDNF/TrkB pathway and restoring potassium chloride cotransporter 2 (KCC2) function. Furthermore, LI-cTBUS attenuated reactive astrogliosis via activation of the transient receptor potential ankyrin 1 (TRPA1) channel, indicating a glial mechanism for ultrasound-induced analgesia. Transcriptomic profiling revealed that PCI altered the spinal transcriptome, whereas LI-cTBUS reversed inflammatory signatures, corrected aberrant BDNF/TrkB signaling, and restored GABAergic transmission. Collectively, these findings demonstrate that LI-cTBUS reprograms reactive astrocytes, suppresses nociceptive signaling, and provides sustained relief from neuropathic pain, underscoring its therapeutic potential for non-invasive spinal neuromodulation.