To investigate the effects of Low-intensity transcranial focused ultrasound (LITFUS)  on brain Aβ clearance, pathological changes, and cognitive function in AD mice, and to preliminarily explore the underlying mechanism.

5xFAD mice were used as an AD model and received bilateral hippocampal LITFUS stimulation for 4 weeks. Fluorescent tracers were injected into the cisterna magna or hippocampus, followed by ex vivo imaging to evaluate CSF influx and interstitial fluid efflux. Aβ levels in the ipsilateral deep cervical lymph nodes (dCLNs) were measured by ELISA to assess brain Aβ drainage. Immunofluorescence staining was performed to detect Aβ deposition, neuroinflammation, and neuronal injury in the hippocampus and prefrontal cortex. Behavioral tests were conducted to evaluate learning and memory. Western blotting was used to examine Piezo1 expression and the downstream CaMKII/eNOS signaling pathway. Hematoxylin-eosin staining was used to assess tissue safety.

Compared with the sham group, LITFUS increased whole-brain CSF tracer influx and accelerated hippocampal interstitial tracer efflux in 5xFAD mice. Aβ levels in the dCLNs were increased, whereas Aβ deposition in the hippocampus and prefrontal cortex was reduced. In addition, neuroinflammation and neuronal injury were attenuated, and learning and memory performance was improved after LITFUS treatment. Western blot analysis showed that LITFUS upregulated Piezo1 expression and activated the downstream CaMKII/eNOS signaling pathway. No obvious tissue damage was observed on hematoxylin-eosin staining.

LITFUS improved brain fluid exchange and Aβ drainage in AD mice, reduced Aβ deposition and related pathological injury, and improved cognitive function. These effects may be associated with activation of endothelial Piezo1 and its downstream signaling pathway. The findings suggest that LITFUS, as a noninvasive physical intervention, may have potential value in improving AD-related cognitive impairment and promoting functional rehabilitation.