OBJECTIVETo observe the expression of GRP78 (glucose regulated protein, GRP78), Caspase-12 and the change of neuron apoptosis in the juvenile rat hippocampus after status convulsive (SC), and to explore the effect of edaravone on them.

METHODSOne hundred and ninety-five juvenile male Sprague-Dawley (SD) rats were randomly divided into normal saline control group (NS group), status convulsive group (SC group) and edaravone treatment group (ED group). Each group was further divided into five subgroups in different executed time points after SC. The rats in status convulsive group were kindled into epilepsy by lithium-pilocarpine method. Expression of GRP78 mRNA and caspase-12 mRNA was detected with reverse transcription-polymerase chain reaction (RT-PCR) method. Expressions of GRP78 and caspase-12 protein were detected with immunohistochemical methods. The neuron apoptosis was observed by TdT-mediated dUTP nick end labeling (TUNEL).

RESULTS(1) Measured by immunohistochemistry the value of OD of GRP78 (0.1480 ± 0.0164, 0.1682 ± 0.0114, and 0.1540 ± 0.0102, respectively, 12 h - 48 h points) and caspase-12 (0.1325 ± 0.0165, 0.1794 ± 0.0213, 0.1525 ± 0.0423, and 0.1309 ± 0.0199, respectively, 12 h-72 h points) positive cells in the SC group increased, there was a significant difference compared with NS group (GRP78: 0.1214 ± 0.0147, 0.1272 ± 0.0177, and 0.1260 ± 0.0157, respectively, 12 h-72 h points. Caspase-12: 0.1050 ± 0.0121, 0.1041 ± 0.0151, 0.1058 ± 0.0222, and 0.1036 ± 0.0186, respectively, 12 h - 72 h points) (P < 0.01, or P < 0.05). By ED intervention GRP78 (0.1550 ± 0.0131, 0.1886 ± 0.0154, and 0.1721 ± 0.0151, respectively, 12 h - 48 h points) positive cells value of the OD increased as compared with SC group (P < 0.01, or P < 0.05). and caspase-12 (0.1211 ± 0.0184, 0.1545 ± 0.0205, and 0.1085 ± 0.0219, respectively, 12 h, 24 h and 72 h points) positive cells value of the A decreased as compared with SC group (P < 0.01, or P < 0.05). (2) Measured by RT-PCR, the expression of GRP78 mRNA and caspase-12 mRNA trend was similar to protein. (3) The TUNEL positive cells in hippocampus CA(1) of SC group (11.41 ± 2.37) were more than that of NS group after the SC 12 h (P < 0.01), reached its highest level at 48 h (28.78 ± 5.11), after the intervention with edaravone (8.98 ± 2.22, 13.09 ± 2.54 and 20.57 ± 4.89, respectively, 12 h-48 h points), TUNEL positive cells showed a significant drop in SC group at 12 h-48 h time points (P < 0.01, or P < 0.05), but still significantly higher than that of the NS group (6.22 ± 1.50, 6.57 ± 1.61 and 6.72 ± 1.14, respectively) (P < 0.01, or P < 0.05), at the 4 h time point (NS group 6.29 ± 1.49, SC group 6.61 ± 1.71, ED group 5.75 ± 1.41) among the three groups, no significant difference in TUNEL positive cells was found (P = 0.759).

CONCLUSIONSThe expression of GRP78 and caspase-12 increased after SC. Edaravone increased expression of GRP78 and decreased expression of caspase-12 in hippocampus rat with pilocarpine-induced seizures, reduced the number of neuronal apoptosis. These results suggest that edaravone may have protective effect against the hippocampal damage caused by status convulsive.