AQP4 expression was elevated in peripheral blood of patients and mice brain with sepsis associated encephalopathy. a) The change of AQP4 levels in peripheral blood of healthy patients, sepsis patients, and SAE patients was detected by ELSA. Healthy controls (n = 20) and sepsis patients without encephalopathy (n = 27), sepsis related encephalopathy (n = 33). Data are presented as the mean ± SD. **p < 0.01, ***p < 0.001, one‐way ANOVA with Tukey's post hoc test. b) The area under ROC curve of SOFA score, APACHE II score, peripheral blood AQP4, and TNF‐α, IL‐6, and IL‐1β of SAE patients. AQP4 has the largest area under the curve. c) Pearson correlation analysis between AQP4 and SOFA score, APACHE II score, TNF‐α, IL‐6, IL‐1β in patients with sepsis associated encephalopathy. d) Representative Western blot bands of AQP4 expression levels in cortex and hippocampus of mice. n = 4–6 mice for each group. Data are presented as mean ± SD. * p < 0.05; ** p < 0.01; *** p < 0.001; One‐way ANOVA with Tukey's post hoc test.