In this study organotypic adult spinal cord slices were used to investigate whether caspases could participate in the apoptosis of motor neurons. The thoracic region of spinal cord was sliced using a tissue chopper and cultured in a medium for 6h. Morphological and biochemical features of apoptosis were assessed by fluorescent staining and terminal deoxynucleotidyl nick end labeling (TUNEL) method respectively. To investigate the role of caspases, general caspase inhibitor, Z-VAD.fmk, and immunohistochemistry for activated caspase-3 were used. After 6h in culture, many motor neurons displayed morphological features of apoptosis. In addition, the neurons appeared TUNEL positive. Z-VAD.fmk not only prevented apoptosis in the motor neurons but also increased motor neurons viability after 6h. At this time point, immunolocalization to activated caspase-3 was also detected in the cytoplasm and the nuclei of apoptotic motor neurons. Results of the present study suggest a caspase-dependent apoptosis in motor neurons of adult spinal cord slices.
