Ginsenoside Rb1 ameliorates endothelial dysfunction in sepsis: Targeting the RhoA/ROCK pathway to modulate mitochondrial homeostasis and inflammation.

BACKGROUND: Sepsis-induced endothelial dysfunction drives organ injury through microcirculatory failure, characterized by barrier disruption and heterogeneous blood flow. Ginsenoside Rb1 (G-Rb1), a bioactive ginseng constituent, exhibits potent anti-inflammatory and antioxidant properties. This study investigates whether G-Rb1 ameliorates sepsis by preserving endothelial barrier integrity via modulating mitochondrial homeostasis and inhibiting the RhoA/ROCK pathway. METHODS: A murine cecal ligation and puncture (CLP) sepsis model and lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells (HUVECs) were employed. Endothelial barrier function, mitochondrial dynamics, and inflammatory responses were assessed via histology, flow cytometry, Western blot, and Seahorse XF analysis. RhoA/ROCK inhibitor (Fasudil) and Drp1 inhibitor (Mdivi-1) served as mechanistic controls. RESULTS: G-Rb1 significantly improved survival in CLP mice and attenuated lung injury. It suppressed pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) in bronchoalveolar lavage fluid and rebalanced T cell percentage. In HUVECs, G-Rb1 restored endothelial junction proteins (VE-cadherin, ZO-1, Claudin-5), reduced ROS/MDA, and enhanced SOD/GSH/ATP levels. Mechanistically, G-Rb1 inhibited RhoA activation and ROCK-mediated Drp1 phosphorylation (Ser616), normalizing mitochondrial fission, membrane potential, and oxidative phosphorylation. CONCLUSION: G-Rb1 alleviates sepsis-induced endothelial dysfunction by suppressing the RhoA/ROCK/Drp1 axis, thereby restoring mitochondrial homeostasis and barrier integrity. These findings highlight G-Rb1 as a promising therapeutic candidate for sepsis management via dual modulation of cytoskeletal dynamics and mitochondrial quality control.