NOX4 and spinal cord injury: Our data showed that overexpression of circItm2b elevated the mitochondrial ROS level, and decreased the content of ATP, furthermore, it increased the expression of Nox4 and reduced the level of Clock and Bmal1, which in keeping with the research of Gaudet et al., who reported that the circadian system in rats was disrupted following spinal cord injury (SCI) due to a reduction in the expression of the core circadian rhythm proteins, Clock and Bmal1 [53].