The expression levels of Claudin-5, ZO-1, and VE cadherin mRNA in lung tissue of ALI group were significantly lower than those in control group (all P < 0.01), and the expression levels of Claudin-5, ZO-1, and VE cadherin mRNA after KGF-2 pretreatment. The gene discussed is CLDN5; the disease is acute respiratory distress syndrome.