INTRODUCTION: Animal models for seizures and epilepsy have played a fundamental role in advancing our understanding of basic mechanisms underlying epileptogenesis and epilepsy. During epileptogenesis and epilepsy, several molecular and cellular changes occur, including alterations in gene and protein expression. MBD3 (Methyl-CpG binding domain 3) protein is a reader of DNA methylation marks, which changed its expression in epileptogenesis. AIM(S): The aim of this study was to determine changes in MBD3 protein expression after acute seizure in the rat brain. METHOD(S): Spraque‑Dawley rats were kept in an enriched environment and were subjected to handling procedure. A single interperitional injection of pentylenetetrazol (PTZ, 40 mg/kg) was used to evoke tonic‑clonic seizure. Control rats (n=16) which were injected by saline and rats after PTZ administration (n=16) were observed for an hour after injection. To examine changes in RNA expression and protein level, animals were sacrificed at selected time points: 1 h, 4 h, 8 h and 24 h after injection. Changes in MBD3 protein levels were examined in the hippocampus, entorhinal, and somatosensory cortex using Western Blot with anti-MBD3 antibody (#A302-528A, Bethyl) followed by ImageJ analysis, whereas changes on RNA level were examined with Real Time PCR. RESULTS: No significant differences were observed in RNA levels in the hippocampus, entorhinal, and somatosensory cortex during 24 h after injection. Western Blot analysis showed an increased level of MBD3 protein at 4 h after seizures evoked by PTZ injection in the somatosensory cortex. PTZ did not affect MBD3 protein expression in the hippocampus and entorhinal cortex at 4 h, 8 h, and 24 h after injection, nor in the somatosensory cortex at 8 h and 24 h after PTZ injection. CONCLUSIONS: These results showed that seizures influence MBD3 protein expression and therefore MBD3 may play an important role in epileptogenesis or epilepsy. FINANCIAL SUPPORT: This work is supported by the Polish Ministry of Science and Education grant 2015/19/B/NZ4/01401.