Controllable permeability of blood-brain barrier and reduced brain injury through low-intensity pulsed ultrasound stimulation

It has been shown that the blood-brain barrier (BBB) can be locally disrupted by focused ultrasound (FUS) in the presence of microbubbles (MB) while sustaining little damage to the brain tissue. Thus, the safety issue associated with FUS-induced BBB disruption (BBBD) needs to be investigated for future clinical applications. This study demonstrated the neuroprotective effects induced by low-intensity pulsed ultrasound (LIPUS) against brain injury in the sonicated brain. Rats subjected to a BBB disruption injury received LIPUS exposure for 5 min after FUS/MB application. Measurements of BBB permeability, brain water content, and histological analysis were then carried out to evaluate the effects of LIPUS. The permeability and time window of FUS-induced BBBD can be effectively modulated with LIPUS. LIPUS also significantly reduced brain edema, neuronal death, and apoptosis in the sonicated brain. Our results show that brain injury in the FUS-induced BBBD model could be ameliorated by LIPUS and that LIPUS may be proposed as a novel treatment modality for controllable release of drugs into the brain.