| Objective:The goal of the present research was to evaluate neuronal damage and glial cell activation in the hippocampus of developing male rats at postnatal day (P)7,15and21, at multiple time points after status epilepticus (SE) induced by lithium-pilocarpine (Li-PC). And to study the relationship between neuronal loss and glial activation.Methods:1. Molding, We chose healthy immature male P7rats(n=65), P15rats(n=65)and P21rats(n=65),and they were divided into blank control group (n=15)and epilepsy group(n=50),respectively. We used lithium-pilocarpine (Li-PC) to induce SE at different age points in the EP group. All the rats of EP group were pretreated with lithium (128mg/kg)18-24hours earlier, then pretreated with atropine sulphate (1mg/kg, i.p.) and15min later were given pilocarpine (i.p.). The doses of pilocarpine were120mg/kg,80mg/kg and60mg/kg, respectively. However, the blank group rats received an equal volume of i.p. normal saline. All the rats were killed at2h、12h、24h、3d and7d after SE, each EP subgroup has10rats at different time points after SE, each control subgroup has3rats.2. Neuronal death was evaluated by Fluoro Jade B (FJB) staining method and Nissl staining method.3. Glial activation states were analyzed by immunohistochemistry for glial markers, GFAP and IBa-1.Results:1. The present research proved that the doses of pilocarpine were effective. Seizure threshold to generalized seizures and the doses of pilocarpine were different at childhood developmental period.2. All the rats were induced behavioral SE.The survival rate of P7and P15rats was100%, however, the rate of P21rats was about60%.3. FJB staining and Nissl staining showed that there was no neuronal damage in the hippocampus of P7EP group rats and all blank control groups rats.Neuronal damage of hippocampal CA1region and DG region was obvious in the P15groug rat pups,howere, CA1, DG and CA3areas in the P21group rats.4. Lithium chloride-pilocarpine caused hippocampal glial activation in the three EP groups. But the expression of GFAP and IBa-1in the P21EP group was higher than the other groups (P<0.05). In the blank control groups, the expression of GFAP in the CA3region of P21rats was highest (P<0.05), and the expression of IBa-1of P7rats was lowest (P<0.05). At the same time, we founded that hippocampal glial cells began to activate at2h after SE, and was sufficient at3d after SE.Conclusion:The effective doses of pilocarpine were different in the developing immature rats. Younger immature rats tend to become tolerant to SE. Hippocampal neuronal damage and glial activation present time-and-age dependant characteristic. And the neuronal damage is related to glial activation. Objective:In the fist part, we found that there was a relationship between neuronal loss and glial activation, and glial activation was notable at3days after SE. Depending on this experimental results, We try to investigate the protective effect of triptolide on hippocampal neuronal loss after lithium chloride-pilocarpine-induced status epilepticus (SE) and the possible mechanisms.Methods:Juvenile male Wistar rats were divided into three groups:(A) control rats, received neither pilocarpine nor triptolide (n=10);(B) rats that received just pilocarpine (n=30);(C) rats that received pilocarpine and triptolide (n=30). Seizure activity was monitored behaviorally and assessed,3days after pilocarpine-induced SE, neuronal death was evaluated by Nissl and FJB staining methods. Glial activation states were analyzed by immunohistochemistry for glial markers, GFAP and IBa-1.Results:Histopathological observations showed that chloride-pilocarpine caused significant hippocampal neuronal loss and glial activation. Pre-treatment with TP efficiently reduced lithium chloride-pilocarpine-induced seizure activities, hippocampal neuron death and glial activation.Conclusion:TP exerts a neuroprotective role in the attenuation of brain damage after SE, possibly by inhibiting glial activation. |
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