OBJECTIVEThe expressions of caspase-1 and cytokines activated by caspase-1 are associated with the pathophysiology of many diseases for its proinflammatory and proapototic peculiarity. However its relationship to brain injury of developing rats following recurrent seizures has not yet been identified. This study aimed to investigate the role of caspase-1 and cytokines activated by caspase-1 in brain injury of developing rats following recurrent seizures.

METHODSA total of 96 postnatal 20 day Sprague-Dawley rats were randomly assigned into Control and Seizure groups. Seizures were induced in the Seizure group by flurothyl inhalation daily for six days. Brain tissues were sampled at 6 hrs, and at 1, 3, and 7 days after last seizure. The expressions of caspase-1, interleukin (IL)-18 and IL-1beta mRNA in the cerebral cortex were detected by RT-PCR. The water content of the brain and the pathological changes of cortex nerve cells were observed. Brain injury was evaluated using a semiquantitative neuropathological scoring system.

RESULTSThe levels of caspase-1 and IL-18 mRNA in the cerebral cortex of the Seizure group were obviously higher than those in the Control group at 6 hrs, and at 1, 3, and 7 days after seizure (P < 0.05 or P < 0.01). The expression of IL-1beta mRNA in the Seizure group exhibited a biphasic pattern: increased significantly at 6 hrs, and at 1 and 7 days post-seizure (P < 0.01), but was not significantly different from the Control group at 3 days post-seizure. Edema, degeneration and necrosis of nerve cells in cerebral cortex, accompanying by inflammatory cell infiltration and apoptosis of nerve cells, were observed under a light microscope in the Seizure group after recurrent seizures. The water content of the brain in the Seizure group increased significantly compared with that in the Control group at 6 hrs, and at 1 and 3 days after recurrent seizures (P < 0.01). The Seizure group had significantly higher neuropathological scores than the Control group at each time point (P < 0.01).

CONCLUSIONSCaspase-1 and cytokines activated by caspase-1 play an important role in the developing brain injury after recurrent seizures.