Possible Role of Protein CPG15 in Hippocampal Mossy Fiber Sprouting Under Conditions of Pentylenetetrazole Kindling

We examined changes in expression of the candidate plasticity-related gene 15 (CPG15) in the dentate gyrus (DG) and hippocampal CA3 region in the pentylenetetrazole (PTZ) kindling model and investigated the role of this gene in the phenomenon of mossy fiber sprouting (MFS). Experimental rats were divided into the control and PTZ groups. The epileptic model was created by intraperitoneal PTZ injection, while control rats were injected with saline. At days 3, 7, 14, 28, and 42 after the first PTZ injection, Timm staining was scored in the CA3 hippocampal area, and a product of CPG15 (protein CPG15) was labeled in the DG stratum granulosum and in the CA3 area using immunohistochemistry. The Timm scores in the CA3 region increased gradually from day 3 and were significantly higher than those in the control within the subsequent period. The level of CPG15 protein in the DG and CA3 area decreased gradually until day 14 and returned to the normal level at day 28. The results obtained indicate, for the first time, that CPG15 may be involved in the process of MFS. Understanding the molecular mechanisms underlying this phenomenon may lead to successful therapeutic interventions that limit epileptogenesis.