COX-2-PGE₂ signaling pathway contributes to hippocampal neuronal injury and cognitive impairment in PTZ-kindled...

Epilepsy is one of the most common neurological diseases. It adversely affects cognitive function. Neuroinflammation has been widely recognized as an important factor involved in the pathophysiology of epilepsy. Cyclooxygenase (COX) is a type of oxidoreductase enzyme that acts in the metabolic pathway converting arachidonic acid to prostaglandins, which mediate inflammatory reactions. The activation of inducible cyclooxygenase-2 (COX-2) is considered to be a precipitating factor of neuroinflammation in the brain. Neuroinflammatory processes in the brain are known to contribute to the cascade of events leading to neuronal injury, which may consequently cause cognitive decline. Here in this study, we showed that pentylenetetrazole (PTZ)-kindled mice exhibited an increased level of COX-2 and its main product prostaglandin E2 (PGE₂) along with neuroinflammation and neuronal injury in the hippocampus. Pharmacological inhibition of COX-2 by celecoxib, however, significantly reduced hippocampal neuroinflammation and neuronal injury. Furthermore, inhibition of COX-2 by celecoxib attenuated cognitive impairment in the PTZ-kindled mice, suggesting that COX-2-PGE₂ signaling pathway mediated neuroinflammation and neuronal injury contributes to cognitive dysfunction in the PTZ-kindled epilepsy mice. Targeting COX-2-PGE₂ signaling pathway in the epileptic brain appears to be a viable strategy for attenuating neuronal injury and preventing cognitive deficits in epilepsy patients.