Repetitive transcranial magnetic stimulation is associated with improved functional recovery and time-dependent changes in apoptosis-related execution-phase markers after spinal cord injury

This study aimed to determine whether repetitive transcranial magnetic stimulation (rTMS) is associated with changes in motor recovery and apoptosis-related pathways after spinal cord injury (SCI), and to characterize the temporal dependence of these effects. A rat model of SCI was established using Allen's method, and rTMS was initiated on day 2 post-injury. Western blot and immunofluorescence were used to quantify apoptosis-related execution-phase proteins, including caspase-3, cleaved caspase-3, caspase-7, PARP1, and cleaved PARP1, and to assess their cellular distribution. Double immunofluorescence of NeuN and cleaved caspase-3 was performed to identify the localization of apoptotic signals. TUNEL staining, HE staining, and BBB scores were used to assess apoptotic cell death, tissue injury, and motor recovery. rTMS was associated with time-dependent changes, with limited effects at early stages but reduced apoptosis-related signaling and improved tissue preservation and functional recovery at later time points. Co-localization of NeuN and cleaved caspase-3 indicated that apoptotic signaling was localized in neurons. These findings suggest that rTMS is associated with reduced activation of apoptosis-related execution-phase signaling after SCI in a time-dependent manner, together with enhanced tissue preservation and functional recovery. The caspase-3/caspase-7/PARP1 cleavage axis may be involved in the biological changes associated with rTMS treatment after SCI.