Propofol Induces Postoperative Depression and Inhibits Microglial Function in Mice

Many patients experience excellent physical recoveries after surgery; however, there are some of them who from suffer mood fluctuation, even depression. Postoperative depression may be resulted from cognitive dysfunction, pain, and a compromised immune system during the surgery. But there is a higher possibility that general anaesthesia may be responsible for the development of depression. Here, we employed one of the most used anaesthetics, propofol, in a mouse model to investigate whether this intravenous anaesthetic compound could cause depressive-like behavioural performance in mice. We found a single dose of propofol caused significant abnormal behavioural performance in tail suspension, forced swimming, and open field tests. We also examined the brain section of these mice and revealed that there was significant reduced expression of the CD11b protein, which demonstrated an inhibition of propofol on microglial function. We investigated the effect of propofol on synaptic protein, SYP, and found there was no notable influence on the protein expression. These above results suggested that propofol treatment might promote the depressive-like behaviours in mice via influencing the microglial cell function. Furthermore, we found the level of the IL-6 cytokine was significantly increased in the brain tissue, which might subsequently cause the activation of the transcriptional factor, STAT3. Our finding may provide a new perspective of further understanding the mechanism of anaesthetic drugs and deciphering the underlying mechanism of postoperative depression.