Low intensity focused ultrasound stimulation targeted on M1 ameliorates neuroinflammation in hemi-parkinsonian rats.

Low intensity focused stimulation (LIFUS) has been proved to improve motor function in Parkinson's disease (PD) animal modules. The aim of this study is to investigate whether LIFUS target on the primary motor cortex (M1) can improve motor deficit in the PD rats. The PD rat model was induced by injection of 6-hydroxydopamine (6-OHDA) in the medial forebrain bundle (MFB). Two weeks after the injection, LIFUS was used on PD rats for two weeks. Behavioral tests were performed including open field test and rotarod test to examine the motor ability of the rats. The activity of microglia and astrocyte were tested to evaluate the inflammation level in the brain. The tyrosine hydroxylase (TH) staining was done to detect the recovery of dopaminergic (DA) neurons in the substantia nigra (SN) and DA fibers in the striatum (STR). LIFUS treatment decreased the resting time in OFT(p<0.05) and increased the latency to falls in the rotarod test(p<0.05) compared with the untreated PD rats. Moreover, LIFUS reduced the inflammation response reflected in microglia and astrocyte activation. Additionally, TH-immunoreactive fibers increased in the STR after LIFUS. These findings demonstrated that LIPUS targeted on M1 can inhibit neuroinflammation and improve movement disorders of PD rats. This study provides a new therapeutic strategy for further clinical application in PD.