Propofol improves learning and memory in post-traumatic stress disorder (PTSD) mice via recovering hippocampus synaptic plasticity

Aims: Propofol, the most commonly used intravenous anesthetic, is known for its protective effect in various human and animal disease models such as post-traumatic stress disease (PTSD). However, it still needs efforts to clarify the effect of propofol on fear memory extinction and the relevant mechanisms. Methods: Fear memory extinction was examined in PTSD mice model. Thirty-six mice were randomly divided into three groups: a shock + propofol group (sh + Pro), shock + normal saline group (sh + NS), and sham group. The mice were treated with propofol (150 mg/kg) or normal saline (of the same volume) intraperitoneally 30 min after the conditioning. These mice's behavior was analysed with contextual test, sucrose preference test (SPT) and Morris water maze (MWM). Additionally, the synaptic plasticity of the hippocampus was examined by long-term potentiation (LTP) and long-term depression (LTD). Key findings: Compared with the sham group, the sh + NS group showed increased freezing time and depressive behavior, meanwhile the sh + Pro group showed minor behavioral changes. What's more, we found that propofol rescued the impaired long-term potentiation (LTP) and long-term depression (LTD) in hippocampus of PTSD mice. All these suggest that propofol can accelerate fear memory extinction and change synaptic plasticity of PTSD mice. Significance: The study proved that propofol can protect the mice from PTSD by reserving synaptic plasticity and brought a new insight into PTSD treatment indicating that propofol maybe a potential cure for PTSD.