Effects of dantrolene on apoptosis and immunohistochemical expression of NeuN in the spinal cord after traumatic injury in rats

Summary Dantrolene has been shown to be neuroprotective by reducing neuronal apoptosis after brain injury in several animal models of neurological disorders. In this study, we investigated the effects of dantrolene on experimental spinal cord injury (SCI). Forty‐six male Wistar rats were laminectomized at T13 and divided in six groups: GI (n = 7) underwent SCI with placebo and was euthanized after 32 h; GII (n = 7) underwent laminectomy alone with placebo and was euthanized after 32 h; GIII (n = 8) underwent SCI with dantrolene and was euthanized after 32 h; GIV (n = 8) underwent SCI with placebo and was euthanized after 8 days; GV (n = 8) underwent laminectomy alone with placebo and was euthanized after 8 days; and GVI (n = 8) underwent SCI with dantrolene and was euthanized after 8 days. A compressive trauma was performed to induce SCI. After euthanasia, the spinal cord was evaluated using light microscopy, TUNEL staining and immunochemistry with anti‐Caspase‐3 and anti‐NeuN. Animals treated with dantrolene showed a smaller number of TUNEL‐positive and caspase‐3‐positive cells and a larger number of NeuN‐positive neurons, both at 32 h and 8 days (P ≤ 0.05). These results showed that dantrolene protects spinal cord tissue after traumatic SCI by decreasing apoptotic cell death.