RESUMO
Objective To investigate the expression and significance of NADPH oxidases Nox2 and Nox4 in mouse colitis. Methods Mouse colitis model was established by using six-to-eight-week-old 129S /SV mice. Mice were randomly divided into 3 groups: control group,1. 5％ dextran sulfate sodium (DSS) group and 3. 0％ DSS group (n = 10 for each group). All of them were fed for 7 days to adapt to the environment. After then,the control group was given drinking water only,colitis was induced by giving drinking water consisted of 1. 5％ DSS or 3. 0％ DSS for 6 days. Weight loss,disease activity index (DAI) and histology were used to quantify the severity of colon inflammation. Oxidative stress indicator,malondialdehyde (MDA) in serum was measured by biochemical methods. The mRNA levels of pro-inflammation cytokines (IL-1β,IL-6 and TNF-α) were quantified by real-time PCR. The protein and mRNA expression of Nox2 and Nox4 in colon tissue of mice was evaluated by immunohistochemistry and real-time PCR,respectively. Results There was no colitis in the control group,while mild and severe enteritis was found in mice in the 1. 5％ DSS group and 3. 0％ DSS group,respectively. The number of goblet cells was decreased significantly in the 1. 5％ DSS group than that of control group (P < 0. 05),and further reduced in the 3. 0％ DSS group (P < 0. 05). MDA was enhanced along with the increased concentration of DSS (P < 0. 05 for both). The expression of Nox2 and Nox4 protein and mRNA was different with the severity of inflammation. The expression of protein and mRNA of both Nox2 and Nox4 were increased in 1. 5％ DSS group compared with the control group (P < 0. 05),and further reduced in the 3. 0％ DSS group (P < 0. 05). Nox2 mostly expressed in the phagocytes and neutrophils; Nox4 mostly expressed in the neutrophils and lymphocytes. Conclusion Nox2 and Nox4 play an important role in the occurrence of mouse colitis.