Microglial ROS production in an electrical rat post-status epilepticus model of epileptogenesis

Objective: Glia are supporting cells of the brain that serve essential functions. Microglia are a type of glia that respond to seizures by changing their shape and releasing free radicals called Reactive Oxygen Species (ROS). Studies showing this have been done in the lab using a chemical called a chemoconvulsant to produce seizures. Thus, it is not possible to know whether the effects are because of the seizures or the drug itself. In a recent paper, the authors used electrical stimulation to produce seizures in rats and looked at production of ROS in microglial cells. The rationale was that knowing this can help guide design of therapeutic strategies for epilepsy.

Results: Acquired epilepsies can be caused by an event like stroke or meningitis, which may be followed by a phenomenon called “epileptogenesis” (the quiet period where the normal brain becomes epileptic). Hence, the disease process is divided into three parts: the period right after the injury, epileptogenesis and epilepsy. In the rats subjected to electrical stimulation, the authors found an increase in production of microglial ROS right after the stimulation but not during epileptogenesis or epilepsy.

Interpretation: Since an increase in microglial ROS was seen only during the initial phase, therapies to decrease ROS should probably be restricted to just the initial phase. More studies need to be done to study how microglial ROS affects seizures, but this study forms a good start.

Summary for specialists