OCLN and acute respiratory distress syndrome: Figure 4H shows that the expression of the intestinal tight junction proteins ZO-1 and occludin was significantly downregulated in the vehicle group, suggesting that the intestinal barrier was impaired in the H1N1-infected mice but that the AC treatment counteracted the trend in the downregulation of ZO-1 and occludin expression and thus effectively inhibited influenza virus-induced colonic epithelial barrier damage in the ALI mice.