[Effects of W-7 on the expression of GRP78 and neuronal apoptosis in immature rat hippocampus after status convulsion].
OBJECTIVE
To investigate the effects of the calmodulin inhibitor W-7 on the expression of the key marker of ERS GRP78 and neuronal apoptosis in the immature rat hippocampus after status convulsion (SC).


METHODS
One hundred and seventeen male Sprague-Dawley rats aged 19-21 days were randomly divided into three groups: normal saline control (control), SC with and without W-7 pretreatment. Each of the 3 groups was further subdivided into subgroups sacrificed at 4, 24 and 48 hrs. SC model was prepared using lithium-pilocarpine. GRP78 mRNA expression in the hippocampus was detected by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). GRP78 protein was ascertained by immunohistochemistry. Neuronal apoptosis was observed with TdT-mediated dUTP nick end labeling (TUNEL).


RESULTS
The expression of GRP78 mRNA was significantly increased in the non-pretreated SC group compared with the control group 24 hrs after injection of saline or lithium-pilocarpine (P<0.01), and the expression of GRP78 protein also increased markedly in the seizure group compared with the control group 24 and 48 hrs after the injection (P<0.01). The expression of GRP78 mRNA and protein in the W-7 pretreatment group was significantly higher than both the control and the non-pretreated seizure groups 24 and 48 hrs after injection. The TUNEL positive cells in the hippocampus CA1 in the non-pretreated SC group 24 and 48 hrs after injection (21.0 ± 2.5 and 29.4 ± 2.8, respectively) were increased compared to the control group (7.1 ± 1.4 and 7.3 ± 1.6, respectively; P<0.01). W-7 pretreatment decreased TUNEL positive cells to 15.0 ± 2.5 and 20.0 ± 2.9 at 24 and 48 hrs after injection compared to the non-pretreated seizure group (P<0.01), but the number of TUNEL positive cells in the W-7 pretreatment group remained significantly greater than in the control group (P<0.01).


CONCLUSIONS
W-7 may up-regulate the expression of GRP78 and reduce the number of apoptotic neurons, thus provides a neuroprotective effect against brain damage following SC.
Department of Neurology, Yuying Children's Hospital Affiliated to Wenzhou Medical College, Wenzhou, Zhejiang 325027, China.
Zhu-Ying
ZY
Zhou
Guang-Qian
GQ
Li
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000037:antagonists & inhibitors*; D006360:Heat-Shock Proteins / Q000235:genetics*; D006624:Hippocampus / Q000378:metabolism*; D020287:In Situ Nick-End Labeling; D008297:Male; D009474:Neurons / Q000187:drug effects*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013226:Status Epilepticus / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology*; D000091342:Endoplasmic Reticulum Chaperone BiP
D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D013449:Sulfonamides; C051684:GRP78 protein, rat; D000091342:Endoplasmic Reticulum Chaperone BiP; C017967:W 7