The Expression Of STIM1and ORAI1in Post-traumatic Epilepsy Rats

Objective: To investigate the expression of stromal interactionmolecule (STIM1) and calcium release-activated calcium channelmodulator1(ORAI1/CRACM1) in cortical brain tissue of post-traumaticepilepsy rats, and to explore the possible role in post-traumatic epilepsy.Methods:84adult SD rats were randomly divided into two groups,control group (42) and experimental group (42). The rats of experimentalgroup received a intracortical injection of100mmol/L FeCl35μl,and theanimals of the control group were administered with a intracortical injectionwith equal saline.Rat models of epilepsy were established by intracorticalmicroinjection of ferric chloride and identified by occurrence of seizures bybehavior observation and recordation continuously in6h later. Six rats wererandomly selected at each time points (on6h,24h,72h,7d,14d,21d,28d)after epileptic seizure. The injected cerebral cortex of rats was resected. ThemRNA expression of STIM1and ORAI1were detected by Real-time PCR.The protein expression of STIM1and ORAI1were detected by Western blotand immunohistochemistry.Results:(1) The post-traumatic epilepsy animal models were successfully established. Typical seizures were observed in experimentalgroup rats after received a intracortical injection of FeCl3, and the attack ratewas84.0%; the control group had no seizures.(2) Real-time PCR: The mRNA expression of STIM1in theexperimental group were significantly higher than those in the control ateach time points (P <0.05, P=0.000),and peaked at72h (P<0.05, P=0.000);Expression of ORAI1mRNA in the experimental group were significantlyhigher than those in the control at each time points (P<0.05, P=0.000), andpeaked at72h (P<0.05, P=0.000).(3)Western blotting: There is no meaning of statistics in the expressionof STIM1protein between experimental groups and the control at6h afterepileptic seizure (P>0.05, P=0.322); Expression of STIM1protein inexperimental group were significantly higher than those in the control at thelatter six time points (P<0.05), and peaked at72h (P<0.05). There is nomeaning of statistics in the expression of ORAI1protein betweenexperimental groups and the control at6h after epileptic seizure (P>0.05,P=0.054); Expression of ORAI1protein in experimental group weresignificantly higher than those in the control at the latter six time points(P<0.05), and peaked at72h (P<0.05).(4) Immunohistochemistry: The protein expression of STIM1inexperimental group was significantly higher than those in the control at the72h time point (t=16.233, P<0.05); the protein expression of ORAI1in experimental group was significantly higher than those in the control at the72h time point (t=17.339, P<0.05).Conclusions: Over expression of STIM1and ORAI1in the cortex ofpost-traumatic epilepsy rats. CRAC may contribute to the formation ofpost-traumatic epilepsy, and may be a potential antiepileptic therapeutictargets.