The impairment of blood-brain barrier function after ICH can lead to the aggravation of persistent cerebral oedema (Keep et al., 2008; Urday et al., 2015; Mittal and LacKamp, 2016); thus, we measured the cerebral water content and found that NOX4 knockdown substantially reduced the cerebral water content in rats and alleviated the degree of oedema (Figure 5F). This evidence concerns the gene NOX4 and brain edema.