Objective To investigate the distribution and expression changes of voltage-gated chloride channel CLC-2 and CLC-3 in rat models with lithium-pilocarpine-induced chronic epileptic,and discuss the significance of these changes in epileptic pathogenesis.Methods Eighty Wistar rats were randomly divided into status epilepticus(SE,n=60)and control(n=20)groups and rats in the SE group were assigned to 3 subgroups according to the different sacrificed times(24 h,14 d and 30 d).Rat models with chronic epileptic in the SE group were induced by lithium-pilocarpine.Immunohistochemistry was employed to observe the changes of voltage-gated chloride channel CLC-2 and CLC-3 in rat's hlppocampal formation different time points after seizure.The mRNA changes of chloride channel CLC-2 and CLC-3 at different time points after seizure were observed by RT-PCR.Results Compared with those in the control group,the quantity of CLC-2 immune positive neurons and the average optical density in the SE group decreased obviously 14 and 30 d after seizure;so was the mRNA expression of CLC-2(P<0.05).Compared with the control group,the SE group showed obviously increased quantity of CLC-3 immune positive neurons and optical density at each area of the hippocampus 24 h after seizure;so was the mRNA expression of CLC-3(P<0.05).Conclusion Seizures at chronic phase have relation with the decreased expressions of CLC-2.