Genetic Rat Models of Absence Epilepsy: A Review on Similarities and Differences with Absence Epilepsy in Human

Nowadays two model groups are reported for the spontaneous occurrence of spike and wave discharges (SWDs) for seizures in untreated rats include GAERS and WAG/Rij rats, which are independently derived by inbreeding of normal wistar rats. Different studies with different approaches revealed that these two rats have similar feature to human epilepsy. In GAERS, SWDs are first detected around 30 days of age. The most SWDs occur around 4 to 6 months. There are not any different in the characteristics of SWDs in the males and females,that represent genetic transmission is autosomal. The frequency of SWDs in these rats is 7-10 Hz. The antiepileptic drugs are able to suppress the seizure attacks. The most important different of seizures in GEARS and human is the higher frequency of SWDs. It is believedthat polygenetic mutation involve in seizures genesis in this rat model. The WAG/Rij strain is a subline of the WAG strain that was derived from wistar supply. SWDs are emerged at around 60 to 80 days in WAG/Rij. At 6 months of age all of the animals show SWDs and itoccurs alternatively until the death of the animals. SWDs in the WAG/Rij rats are very age dependent. Generally burst activities last 1–30 s and spike-wave frequency is 7–11 Hz in the cortical EEG of adult WAG/Rij rats. Behavioral manifestation of seizures is same as GAERSrats. It is noticeable that beside of high frequency of SWDs, the age of SWDs initiation is different from human. The pharmacological responses to anti-epileptic drugs in these rats are same as human.In conclusion,although GAERS and the WAG/Rij strains of wistar ratshave limitations, but they have asserted to be valid and predictive models of human epilepsy.