The Relationship Of Hippocampal Mossy Fiber Sprouting And CPG15Expression In The PTZ Kindling Model

Object To observe the expressional changes of Cpg15protein in the stratum granulosum of dentate gyrus and the CA1,CA3of hippoca-mpus associated with the changes of hippocampal mossy fiber sprouting in the pentylenetetrazole (PTZ) kindling model and to investigate the role of Cpg15in epileptogenesis.Methods90healthy male Sprague-Dawley rats were divided randomly into control and PTZ treated groups. The PTZ treated rats were intraperitoneally injected PTZ (30mg/kg) every24hours and stopped injection once were kindled. The control rats were intraperi-toneally injected0.9%saline at the same time. Seizure manifestations were evaluated according to Racine. At3d,1w,2w,4w,6w after the first PTZ injection, Timm staining was scored at different times in the CA3of hippocampus and dentate gyrus. The protein of Cpg15was analyzed at different times in the stratum granulosum of dentate gyrus and the CA1,CA3of hippocampus, by using immunohistochemistry.Results1. Animal modelSubsequent injection with the same dose of PTZ induced convulsive responses of gradually increasing severity. After21-28injections(23.6±2.0days),95.8%animals were kindled, the mortality is5%. The control rats have not seizures.2. Changes of hippocampal mossy fiber sproutingThe Timm scores in the CA3region, which gradually increased from3d to2w,were significantly higher than that in controls at different times(P<0.05) and maintained high level in the4w,6w groups. There were no significantly differences in supragranular region between the PTZ treated groups and the control groups at different times.3. Changes of Cpg15protein expressionThere was a gradually decrease of Cpg15protein level in dentate gyrus and the CA1, CA3of hippocampus. All of the regions decreased to the nadir at2w and increased to normal level at4w. But Cpg15protein level of dentate gyrus and C A3decreased again at6w.Conclusions1. The changes of Cpgl5expression might advance the procession of mossy fiber sprouting.2. The change of Cpgl5expression in CA3region might play a more important role in the onset of epilepsy than that in dentate gyrus.