Effects of thymoquinone on penicillin-induced epileptiform activity in rats

Thymoquinone (TQ) is derived from Nigella sativa (NS) which is a traditional medical plant and used as a food additive. Aim of this study is to investigate acute effects of thymoquinone, which has been shown anticonvulsant, anticancer, antioxidant and neuroprotective effects, on experimental penicillin-induced epilepsy model in rats. In this study 56 adult male Wistar rats were used, and these rats were divided into 7 groups as sham, control (saline), thymoquinone (non-induced with penicillin), vehicle (dimethylsulfoxide, DMSO), and the doses of 10 mg/kg, 50 mg/kg and 100 mg/kg of thymoquinone. All of the substances were administered intraperitoneally except penicillin. After rats were anesthetized with administration of the 1.25 g/kg dose urethane intraperitoneally, the left part of the cortex was opened and the electrodes were placed on somatomotor area. At the 30th minute of thymoquinone application, epileptiform activity was induced by intracortical (i.c.) administration of penicillin (500 IU, 2.5 μl). Obtained electrocorticographic (ECoG) data from recordings were analyzed by software. The first spike latency, spike wave frequency, and spike wave amplitude of epileptiform activity were analyzed statistically. There were no epileptiform acitivty in sham and thymoquinone (non-induced with penicillin) groups. Thymoquinone at the doses of 10 mg/kg, 50 mg/kg and 100 mg/kg significantly increased the latency time to onset of first spike wave and decreased the frequency versus control and DMSO groups. However, comparing spike wave amplitude of epileptiform activity there were no significant difference between the groups after 20th minutes from penicillin administration. Consequently, the results of the present study show that administration of thymoquinone has antiepileptic effect in penicillin induced model of epilepsy in rats and it may be a potential antiepileptogenic drug in future.