To investigate whether As-IV protects against endothelial dysfunction induced by high glucose through the P38 MAPK signaling pathway, we isolated and cultured endothelial cells from SD rat aorta with or without As-IV and SB203580 in a high glucose environment for 48 h to further examine the effect of As-IV and SB203580 on eNOS and NO levels in RAOEC. The gene discussed is MAPK14; the disease is endothelial dysfunction.