Abstract: ObjectiveTo explore the influences of age and duration of status convulsivus （SC） on mitochondrial membrane potential (△Ψm） in hippocampus. MethodsConvulsive seizures for 30 min or 3 h (30 min SC or 3 h SC) were induced in 80 infant (20 d after birth) and 80 adult Wistar rats (IRs ＆ ARs respectively) with lithium-pilocarpine ip. The rats were sacrificed at 6 different time points from the 3rd hour to 7th day after SC termination. The mitochondrial △Ψm in hippocampal cells was determined with flow cytometry. ResultsThe mitochondrial △Ψm in hippocampal cells started to decrease at the 3th hour after SC in both IRs and ARs. The bottom level was reached at the 6th hour after SC ［(6.08±0.43) in IRs and (5.70±0.63) in ARs ) ］. Both of them were significantly lower than that of control group (P<0.01） and began to increase at 12th hour after SC. On the 7th day after 30 minutes SC, the level of mitochondrial △Ψm in IRs increased to the level of control, while the level in ARs was still lower than that of control (P<0.05）. At the 3rd hour, the 3rd and the 7th day after SC, the levels of mitochondrial △Ψm in IRs were obviously higher than those in ARs. Compared with the same time point after 30 min SC, the levels of mitochondrial △Ψm at the 3rd and the 6th hour after 3 h SC were much lower in different age groups (P<0.05）. Except the effect of the age-related difference, there was a positive correlation between the duration of SC and the changes of mitochondrial △Ψm in partial correlation analysis （r=0.71，P<0.05）. ConclusionSevere seizure could induce the mitochondrial △Ψm decreased in hippocampus. Age and duration of SC were important factors associated with the mitochondrial △Ψm decrease. There may be an internal protective response against brain damage in premature brain.

Key words: status convulsivus, mitochondrial membrane potential, age, duration, flow cytometry, rats