Establishment of a rhesus monkey model of chronic temporal lobe epilepsy

Objective To describe a rhesus monkey model of temporal lobe epilepsy (TLE) established via repetitive unilateral intra-amygdala kainic acid (KA) injection and provide experimental basis for epileptogenic network and related research. Methods Eight male adult rhesus monkeys were randomly divided into KA injection group (n=6) and saline injection group (n=2). Brain stereotaxic technique, micro catheter implantation into the right amygdaloid nucleus, subcutaneous bladder connection, and continuous video-EEG monitoring were performed, and KA or saline injection into their right amygdala was achieved. Interictal epileptic discharges (IEDs), ictal discharges and behavioural performance between the two groups were compared right after injection and within 6 months of first discharge. Results Typical IEDs were recorded in the 6 monkeys from KA injection group after 2-4 times of KA injection, with focal spike waves discharges at the right temple area as manifestation; ictal discharges were recorded in 4 monkeys, with discharge patterns of discharges from the right temple area to the whole brain as manifestation, and during epileptic attack, these 4 monkeys suddenly stopped and dumbfounded without obvious limb seizures. Monkeys from the saline injection group showed no obvious abnormal behaviors. Conclusion Through a modified protocol of unilateral repetitive intra-amygdala KA injection, a rhesus monkey model with high similarity of behavioral and brain electrical features to TLE is developed. Key words: Rhesus monkey; Animal model; Temporal lobe epilepsy; Electroencephalogram; Kainic acid