Protective effect of high-dose methylprednisolone on the immature rats with infantile spasms

Objective Infantile spasms(IS)is the most common intractable epileptic encephalopathy during infancy, but there is the lack of animal experiment.By building IS animal model, the study discusses whether high-dose methylprednisolone has the protective effect on the immature rats of infantile spasms. Methods Sprague-Dawley immature rats were randomly assigned to 3 groups on postnatal day 10(P10): control group、model group Ⅰ and model group Ⅱ, thirty rats in each group.Immature rats in model group Ⅰ and model group Ⅱ were injected NMDA intraperitoneally to induce seizures.The rats in the model group Ⅱ were injected intraperitoneally methylprednisolone on postnatal day 11, 12 and 13.The clinical behavior of rats were observed and recorded.Neuronal apoptosis was detected by TUNEL.Immunohistochemistry and real-time PCR were used to analyze the expression of Bax, Bcl-2, caspase-3 in hippocampus. Results (1)83.3% of rats in model group Ⅰ had seizures, and none of rats in model group Ⅱ had seizures on postnatal day 13.(2)The apoptotic cell number of brain tissues: model group Ⅱ(14.37±2.02)were lower than model group Ⅰ(25.67±1.52)and higher than control group(9.00±2.50), the difference was statistically significant(all P<0.05). (3)Bax protein and mRNA expression levels in model group Ⅱ(44.55±3.58, 2.35±1.01)were lower than model group Ⅰ(58.05±4.62, 3.27±0.95)and higher than control group (28.90±5.14, 1.68±0.50), there was significant difference(all P<0.05); (4)Caspase-3 expression levels of mRNA in model group Ⅱ (5.99±1.75) were lower than those in group model group Ⅰ(7.88±1.60)and higher than those in control group(3.60±1.70), there was significant difference(all P<0.05). Conclusion High-dose methylprednisolone can reduce NMDA-induced seizures in the IS immature rats.High-dose methylprednisolone has protective effect on the NMDA-induced IS immature rats, which may be relation to weakening seizures and decreasing apoptosis. Key words: Methylprednisolone; Infantile spasms; Apoptosis