MMP9 and ischemia: Consistently, propofol was found to protect the BBB by decreasing MMP‐9 expression and improve the neurobehavioral outcome in rats.26 Others also reported that propofol could reverse ischemia‐downregulated expression of claudins and occludins, thus exerting protective effect on BBB in rabbits.16 In this study, we demonstrated that the neuroprotective effect of propofol against hypoxia‐impaired BBB was correlated with increased ZO‐1 expression and decreased ZO‐1 phosphorylation.