Further research showed that EA preconditioning for 5 days promoted the expression of HO-1 mRNA and protein levels in ALI lung tissue, and the protective effect of EA preconditioning on septic lung injury disappeared after tail vein injection of the HO-1 inhibitor ZnPP IX, indicating that acupuncture protects the lungs by promoting the expression of HO-1 (62). This evidence concerns the gene HMOX1 and acute respiratory distress syndrome.