AimTo study the effect of angiotensin Ⅱ (AngⅡ) on cytoskeleton rearrangement of endothelial cells and the mechanisms within it.MethodsHuman umbilical vein endothelial cells (HUVEC) were treated with AngⅡ (10－6 mol/L) for different time points.The morphological images of filamentous actin (F-actin) cytoskeleton were observed with confocal laser scanning microscope.The phosphorylated protein expression of mitogen-activated protein kinase (MAPK) was tested by Western blotting.ResultsF-actin was mainly enriched along the cell membrane, and well distributed in normal HUVEC; After treatment with AngⅡ, most of the peripheral fibers disappeared, dense stress fibers were observed in the cytoplasm and paracellular gaps formed in a time-dependent manner.AngⅡ increased the phosphorylation of p38 MAPK, JNK1/2 and HSP27, but not ERK1/2.Furthermore, SB203580 (a p38 MAPK specific inhibitor) completely attenuated AngⅡ-induced formation of actin stress fibers and paracellular gaps.In contrast, SP600125 (a JNK1/2 specific inhibitor) had no effect on these responses.ConclusionAngⅡ induces F-actin rearrangement in HUVEC through the activation of p38 MAPK/HSP27 pathway， which results in cytoskeletal damage.