An Experimental Study On The Basics Of Molecular Biology And Their Regulation For The Resistance To Brain Damage Induced By Seizure In Immature Brain

Part Ⅰ A Dynamic Study on Neuron Death Induced by Different Seizure Types【objective】To explore dynamic change of neuron death after SC evoked by lithium-pilocarpine and to confirm the generalized feature on this protective mechanism in different seizure types.【Methods】Status convulsion was evoked by lithium-pilocarpine subcutaneously and intraabdominally injected into 130 healthy infant rats(19 days) and adult rats(2 months) respectively. Different features of SC were compared between two groups. Dynamic process of neuron death and the activity of serum neuro-specific enolase were investigated by HE stain,TdT-mediated dUTP nick end labeling, flow cytometry and enzyme-linked immunosorbent assay at the 15th,30th min and the 1st,2nd,4th,8th hour after SC respectively. 【Results】 ①The average duration from the injection with lithium-pilocarpine was 13.3±5.63mins in infant rats, and 22.5±5.66mins in adult rats; ②The proportion of the 4th or 5th degree of severity at seizure onset was 68% in infant rats and 18% in adult rats; ③Although counting of the died neurons was physiologically higher in normal infant rats than in adult rats, the counting of positive neurons by TUNEL stain in mature brain(524±26) remarkably increased and exceeded that in premature brain(465±26) at 30min after SC. Although continuously observed until 8 hour after SC, the counting of apoptotic neurons in mature brain was also remarkably higher than that in infant brain. Change of neurons in apoptotic early events detected by flow cytometry was as same with the result of TUNEL; ④Comparing with infant rats, the increasing of activity of serum neuro-specific enolase after SC was higher in adult rats. There was striking difference of the activity at 30min after SC between adult rats and infant rats.【Conclusions】①Premature brain seemed more likely prone to have SC than adult brain evoked by stimulants;②A protective mechanism to brain damage with inhibiting apoptotic process in premature brain duringSC was well reconfirmed by different animal SC models induced by lithium-pilocarpine. It was indicated that the protective mechanism to brain damage in premature brain could be presented in most severe seizures of different types.【Key words】 status convulsion,immature brain,apoptosis...