The Relationship Between Dynamic Expression Of FAKpY397and Mossy Fiber Sprouting In Hippocampus Of PTZ Kindling Model

Object To observe the dynamic expression of FAKpY397protein in rat hippocampus during the pentylenetetrazole (PTZ) kindling process and the role of FAKpY397in the course of mossy fiber sprout-ing and epileptogenesis.Methods135healthy male Sprague-Dawley (SD) rats were divided randomly into control and PTZ treated groups. The PTZ treated rats were intraperitoneally injected PTZ (35mg/kg) every24hours and stopped injection once they were kindled. The control rats were intraper-itoneally injected0.9%saline at the same time (Seizure manifestations were evaluated according to Racine). The experimental and control group rats were equally divided into5subgroups at time points3day (3d)、1week(1w)、2weeks(2w)、4weeks(4w) and6weeks(6w) after the first injection. Each subgroup was subsequently divided into3panels for the following tests respectively:(1) The expression and distribution of FAKpY397were analyzed at different time in the regions of hippo-campus by immunohistochemistry and immunofluorescence;(2) The expression of FAKpY397protein in rats’hippocampi by Western Blot;(3) Timm staining and score. There are6rats in each PTZ treated panel and3rats in ench control panel.Results1. Animal modelSubsequent injection with the same dose of PTZ induced convul-sive responses of gradually increasing severity. After21-28injec-tions(23.1±2.3days),93.75%animals were kindled, the mortality is4.44%. All the kindled rats were developed spontaneous recurrent sei-zures (Racine I to Racine Ⅲ). The control rats have no seizures and behave normally.2.Western Blot results showed that in the experimental group, the expression of FAKpY397protein had a slight decline at3d, then gradu-ally increased from1w after the first PTZ injection, reached peak at4w, and then had a decline at6w. Except3d group(P>0.05), the protein level at all the time points were higher than the control group(P<0.05).3.Immunohistochemical and immunofluorescence results showed that FAKpY397, which mainly distributed in the cytoplasm, widely expressed in hippocampus. The expression of FAKpY397in CA3grad-ually increased since3d, reached peack at4w, and then had a decline at6w. The protein levels at all of the time points were higher than the con-trol groups(P<0.05).4. Changes of hippocampal mossy fiber sproutingThere was no obvious mossy fiber sprouting in the CA3area of the control rats at different times. In the experimental group the Timm scores in the CA3region gradually increased sence3d, reached peak at4w, and then had a decline at6w. The Timm scores of the experimental groups were significantly higher than that in controls at different times(P<0.05).ConclusionsThe increased expression of FAKpY397in CA3area of Hippo-campus may promote mossy fiber sprouting and then result in epilepsy.