Effects Of Cell Cycle Inhibitor On The Neuronal Apoptosis And Astrocyte Proliferation After Status Epilepticus

Objective To investigate the effects of olomoucine, a cyclin dependent protein kinase(CDK) inhibitor, on the neuronal apoptosis and astrocyte proliferation after lithium-pilocarpine induced rat status epilepticus (SE) .Methods Fifty six male SD rats were randomly divided into 3 groups: SE was induced with lithium and pilocarpine intraperitoneally (ip.). Olomoucine was dissolved in 50% dimethyl sulfoxide (DMSO) and infused 1.75μmol/day intra-cerebroventricularly(i.c.v) 40 min after SE for 3 days. Correspondingly, SE group was infused vehicle solution containing 50% DMSO. Control group was injected ip. 1ml physiological saline replaced lithium and pilocarpine and was infused i.c.v.vehicle solution containing 50% DMSO. The cortex and hippocampus of 6 rats from each group were taken out 6 hours after SE. Semiquantitative RT-PCR was used to detect the mRNA expression of inflammatory cytokines such as IL-1βand TNF-α. Entorhinal cortex and hippocampus of another 6 rats in each group were taken after 3 days and 60days after SE for immunostaing. Immunofluorescence ( IF) staining was used to detect the expression of NeuN ,CyclinB1, TUNEL and GFAP.Results Semiquantitative RT-PCR showed that the mRNA expressions of IL-1βand TNF-αincreased in SE group compared to those in control group. After olomoucine treatment, there was a downregulation of mRNA expressions of IL-1βand TNF-αof hippocampus(p< 0.05),except TNF-αof cortex. IF staining demonstrated that neuronal apoptosis and CyclinB1 expression were increased in SE group, which were greatly inhibited by olomoucine (P<0.05). Meanwhile GFAP was increased in SE group, which were greatly inhibited by olomoucine demonstrated by IF staining.Conclusion SE induced cell cycle protein activation,neuronal apoptosis and astrocyte proliferation. Olomoucine treatment can inhibite cell cycle protein B1 expression, GFAP expression and inflammatory cytokines production such as IL-1βand TNF-αsecretion, thus decrease neuronal death,astrocyte proliferation and provide neuroprotection after SE, which suggest a potential promising therapeutic target for epilepsy treatment.