Mechanisms of Intermittent Theta-Burst Stimulation Upregulates TFEB and Restores Autophagy to Play a Neuroprotective Role in the Acute Phase After Cerebral Ischemia Reperfusion

Repetitive transcranial magnetism (rTMS) exerts neuroprotective function in the cerebral ischemia/reperfusion (I/R) injury during the early stage. Intermittent theta-burst stimulation (iTBS), a more time-efficient modality of rTMS, improves the efficiency without at least decreasing the efficacy of the therapy. However, little is known about the neuroprotective mechanisms of iTBS. We aimed to investigate the potential regulatory mechanisms by which iTBS attenuates the early stages of nerve injury after I/R in rats. In in vitro experiments, a therapeutic regimen of iTBS was administered to primary cortical neuronal cells. The Cell Counting Kit-8 (CCK-8) assay was then used for determination of cell viability. The expression of autophagy, ferroptosis-related markers was detected by protein immunoblotting. Mitochondrial membrane potential was examined using JC-1, and mitochondrial reactive oxygen species (ROS) production was measured using MitoSOX staining to assess mitochondrial ROS production. In in vivo experiments, rats were stimulated with iTBS or 10 Hz rTMS. Expression of autophagy and ferroptosis-related markers were detected by protein immunoblotting, and the effects of transcranial magnetic stimulation on oxidative stress in rat serum were further investigated. We also measured the motor function of rats by behavioral tests, in addition to observing neuronal cells in the cortex of rats by Nissl staining and HE staining. In this way, we investigated the mechanism of iTBS to attenuate the nerve injury after I/R in rats. The results of in vitro experiments showed that iTBS reduced neuronal cell injury after OGD, increased mitochondrial autophagy, thereby reducing mitochondrial ROS generation, restored the decrease in mitochondrial membrane potential, and attenuated ferroptosis. In in vivo experiments, we compared the effects of two common treatment modalities, iTBS and 10 Hz rTMS, and investigated the mechanism by which magnetic stimulation exerts a protective effect on neuronal cells, demonstrating that it was able to alleviate the nerve damage of I/R by upregulating the TFEB level, and improved the motor coordination and balance ability of rats. In addition, the results showed that the therapeutic effect of iTBS was not inferior to that of 10 Hz rTMS model. In the present study, we compared the effects of these two common therapeutic modalities in in vivo experiments and investigated the mechanism by which magnetic stimulation exerts a protective effect on neurons. In addition, iTBS can reduce the cost per treatment by several times without compromising the therapeutic efficacy, and can be a practical and less costly intervention.