Rho kinase inhibitor Y-27632 prevents partially burn serum-induced endothelial barrier dysfunction / 中国病理生理杂志

ABSTRACT

AIM: To investigate whether small GTPase RhoA's downstream effector Rho kinase mediates burn serum-induced endothelial hyperpermeability. METHODS: Primary cultured rat dermal microvascular endothelial cells (DMECs) were exposed to serum isolated from burned or sham burn rats for 6 hours and 8 hours, respectively, and did or didn't pretreated or post-treated with Y-27632 (30 ?mol/L), a specific inhibitor of Rho kinase. ECs were then prepared for routine scanning electron microscopy observation, or stained with rhodamine-phalloidin for F-actin visualization. Permeability to FITC-albumin was evaluated using EC monolayers. RESULTS: Stimulation with 15% burn serum for 6 h changed the ultrastructure on cellular surface of DMECs with appearance of ripple marks instead of microvillus. The small protuberances at cellular lateral were shorten and the gaps were seen between adjacent cells. Post-treatment of Y-27632 reversed the changes of ultrastructure on the cellular surface. Burn serum induced a striking reorganization of actin cytoskeleton with a weakening of fluorescent intensity of the peripheral filament bands and formation of the long and thick stress fibers, lamellipodia and filopodia. The stress fibers were diminished by pretreatment or post-treatment of Y-27632. But lamellipodia and filopodia were not influenced by pretreatment or post-treatment of Y-27632. Pre-treatment of Y-27632 also attenuated significantly the increase in EC monolayer permeability stimulated by burn serum for 6 h. However, post-treatment of Y-27632 could not attenuated burn serum-induced endothelial hyperpermeability response although their Pa values were lower than simple burn serum group's. CONCLUSION: These findings indicate that Rho kinase is involved in the mediation of burn serum-induced endothelial actin cytoskeleton reorganization and early stage of barrier dysfunction. [