Fig 1: Generation of Nox4-/-mice. Schematic representation of (A) Nox2 and (B) Nox4 deletion using CRISPR/Cas9 technology. The resulting heterozygous and homozygous mice were determined by genotyping PCR using a specific Nox2 or Nox4 deletion site. (C) Immunofluorescence images for NOX4 on the untreated colon and 2.5% DSS-treated colon frozen sections (immunohistochemistry [IHC]-Fr) (left). IHC for NOX2 on the untreated colon and 2.5% DSS-treated colon paraffin-embedded sections (IHC-P) (right). (D) Sirius-red staining showing the fibrotic area in red. The graph represents the measurement of the fibrotic area using ImageJ (National Institutes of Health). Intracellular levels of ROS in the (E) untreated and (F) DSS-treated groups assessed using DCFH-DA staining followed by flow cytometry. Data are expressed as means ± SD. *P < .5 and **P < .01 compared with WT. bp, base pair; DCFH-DA, dichloro-dihydro-fluorescein diacetate.