The KLF4Expression Changes During The Process Of Mossy Fiber Sprouting In Hippocampus Of PTZ Kindling Model

Object To observe the expression changes of KLF4protein in the CA1, CA3and dentate gyrus of hippocampus during the process of mossy fiber sprouting in the pentylenetetrazole (PTZ) kindling model and to investigate the role of KLF4in epileptogenesis.Methods90healthy male Sprague-Dawley rats were divided randomly into control (30rats) and PTZ treated (60rats) groups. The PTZ treated rats were intraperitoneally injected PTZ (30mg/kg) every24hours and stopped injection once they were kindled. The control rats were intraperitoneally injected0.9%saline at the same time. Seizure manifestations were evaluated according to Racine. At the3rd day,1st week,2nd week,4th week,6th week after the first PTZ injection, Timm staining was scored at different times in the CA3and dentate gyrus of hippocampus. The KLF4protein was analyzed at different times in the CA1, CA3and dentate gyrus of hippocampus, by using immunohistochemistry.Results1. In animal models, convulsive responses with gradually increasing severity were induced by subsequent injection with the same dose of PTZ. After21-28injections (24.5±2.3days),100%animals were kindled, and the mortality is2.2%. The control rats have no seizure.2. KLF4protein expressionIn control group, there was a gradually increase of KLF4protein level in the CA1, CA3and dentate gyrus regions of hippocampus from the3rd day to1st week, then kept no change until the6th week. In PTZ treated group, unlike the control one, KLF4protein expression in the CA1, CA3and dentate gyrus regions of hippocampus didn’t increase after the3rd day, but kept a stable level until the6th week. Between two groups, CA1region had significant differences at the3rd day,1st week; CA3region had a significant difference at the1st week, and dentate gyrus region had significant differences at the1st week,2nd week.3. Changes of hippocampal mossy fiber sproutingThe Timm score in the CA3region of PTZ treated group, having begun gradually increasing from3d, got the highest score at the6th week and were significantly higher than that in controls at the2nd week,4th week,6th week (P<0.05). The Timm score in the dentate gyrus region of PTZ treated group, having begun increasing from the4th week, got the highest score at the6th week and were significantly higher than that in controls at the6th week (P<0.05). There was no significant difference in CA3and dentate gyrus regions among different times in control group.ConclusionThe decrease of KLF4expression in hippocampus of PTZ kindling rats model can promote the process of mossy fiber sprouting at early stage.