Additive Enhancement of Neurovascular Regeneration and Functional Recovery by Combined MSC-Exosomes and Low-Intensity Pulsed Ultrasound in Ischemic Stroke Rats.

Cerebral ischemic stroke (CIS) leads to high mortality and disability due to cerebrovascular obstruction. Current therapeutic approaches such as thrombolysis have limitations, and many patients suffer from long-term functional impairments, so new treatment strategies are urgently needed. Both low-intensity pulsed ultrasound (LIPUS) and mesenchymal stem cell-derived exosomes (MSC-EXOs) have demonstrated some therapeutic potential for CIS, but their efficacy is less pronounced when used alone. Therefore, this study aims to evaluate whether the combination of MSC-EXOs and LIPUS exerts an additive effect in the treatment of cerebral ischemic stroke. Adult rats subjected to middle cerebral artery occlusion (MCAO) were randomly assigned to sham, MCAO, MSC-EXO, LIPUS, or combination groups. Outcomes were assessed using the modified Neurological Severity Score (mNSS), corner and Y-maze tests, histological staining (HE and immunofluorescence), transmission electron microscopy (TEM), and quantitative real-time polymerase chain reaction (q-PCR). The combination group showed notable improvements in neurological function, with the highest proportion of cluster of differentiation 31 (CD31)/alpha-smooth muscle actin (α-SMA)/doublecortin (DCX)-positive immunofluorescence area, up-regulation of circular RNA SCMH-1(circSCMH-1), and the best restoration of synaptic ultrastructure. Compared with MSC-EXOs or LIPUS alone, the combined treatment appeared to have an additive effect, supporting neurovascular regeneration and functional recovery after cerebral ischemic stroke.