Emerging evidence has shown that long noncoding RNA (LncRNA) is involved in the development of epileptogenesis. However, the expression profile and the biological function of FIX in epilepsy remains unclear. This study aimed to provide functional evidence and elucidate the molecular mechanisms by which the FTX affects status epilepticus (SE) induced hippocampal apoptosis. SE rat model was introduced by intraperitoneal injection of lithium chloride and pilocarpine. Our results showed that FTX is notably reduced in the hippocampus. Moreover, the in vivo overexpression of FIX inhibited SE-induced hippocampus neuron apoptosis. Mechanically, we found that FIX negatively regulated miR-21-5p expression by targeting its 3'UTR to regulate neuron apoptosis. Upregulation of miR-21-5p attenuates anti-apoptosis property of FTX overexpression by regulating SOX7 expression in epileptiform hippocampal neurons. Collectively, our study for the first time demonstrated the anti-apoptosis ability of FTX during epileptogenesis and uncovered a novel FIX-mediated mechanism in SE-induced neural apoptosis by targeting miR-21-5p/SOX7 axis, which provides a new target in developing lncRNA-based strategies to reduce SE-induced hippocampal neuron apoptosis. (C) 2019 Elsevier Inc. All rights reserved.