The Impact of Environmental Enrichment in Rats Subjected to the Lithium-Pilocarpine Model: Behavioral Assessment and Molecular Changes in the Hippocampus - Abstract
Epilepsy is a neurological condition characterized by unpredictable recurrent seizures that affects about 50 million people worldwide. In Temporal Lobe Epilepsy (TLE), the most common form of epilepsy in adults, seizures are often resistant to drug treatment. Environmental enrichment (EE) has positive effects on the psychological and physiological well-being of the animals and provides news insights into mechanisms of experience-dependent plasticity, including neurogenesis and synaptic plasticity.
Objectives: Evaluate the impact of EE on behavioral changes (latency and frequency of seizures, cognitive process and anxiety) in rats subjected to lesional epilepsy model induced by lithium- pilocarpine (LIP) and changes in BDNF levels in the hippocampus.
Methods: Wistar rats were exposed to an EE protocol and to a standard environment since weaning (PND 21) for 5 weeks. After this period, the animals of both groups (EE and standard) were randomized and injected with LIP or lithium saline solution and video-monitored for 60 days to evaluate the latency and the frequency of seizures. After this period we performed behavioral tests: Elevated Plus Maze (EPM), Open Field Test (OFT), Rearing and Novel Object Recognition (NOR) to evaluate memory and anxiety. The BDNF expression was assessed in the hippocampus by ELISA method.
Results: EE decreased hyperactivity, preserved short-term memory and increased the latency to the onset of spontaneous seizures of LIP rats compared to LIP rats of conventional environment. However, there were no difference in anxiety level and in the total number of seizures between conventional and EE groups. BDNF expression was increased in the hippocampus of rats LIP exposed to EE compared to LIP of conventional environment.
Conclusions: EE is a safe and effective strategy to reduce behavioral changes caused by spontaneous seizures.