Ginsenoside Rb1 protects hair cell-like HEI-OC1 cells against apoptosis by inhibiting the activation of the Fas system induced by the RhoA/ROCK/LIMK1 pathway.

BACKGROUND: Sensorineural hearing loss (SNHL) is a prevalent clinical disorder in otorhinolaryngology, with cochlear ischemia/reperfusion (I/R) injury-induced hair cell apoptosis being a core pathogenic mechanism. Ginsenoside Rb1 (Rb1), a major active component of Panax ginseng, exhibits potent anti-apoptotic and neuroprotective effects, but its role and underlying mechanism in cochlear I/R injury remain elusive. METHODS: The hair cell-like HEI-OC1 cell line was employed to establish an in vitro cochlear I/R injury model via oxygen-glucose deprivation/reperfusion (OGD/R). Cell viability was evaluated using the CCK-8 assay to screen for the non-cytotoxic concentration of Rb1. LIMK1 knockdown was achieved by transfection with si-LIMK1, and the knockdown efficiency was verified by RT-qPCR and Western blot. Flow cytometry with Annexin V-FITC/PI staining was used to detect cell apoptosis. Western blot was performed to measure the protein expression levels of key molecules in the RhoA/ROCK/LIMK1 pathway and Fas system. The Rho/ROCK pathway inhibitor Y-27,632, the RhoA activator LPA, and Fas agonist antibody Jo2 were used to validate the regulatory relationships among the pathways. RESULTS: OGD/R significantly induced HEI-OC1 cell apoptosis, accompanied by activation of the RhoA/ROCK/LIMK1 pathway and Fas system. Rb1 pretreatment attenuated the OGD/R-induced reduction in cell viability and increase in apoptosis, while inhibiting the activation of the RhoA/ROCK/LIMK1 pathway and Fas system. LIMK1 knockdown attenuated OGD/R-induced Fas system activation and cell apoptosis. Notably, LPA attenuated the protective effects of Rb1 and restored RhoA/ROCK/LIMK1-related protein expression, whereas Jo2 attenuated Rb1-mediated protection without affecting the upstream pathway. CONCLUSIONS: Ginsenoside Rb1 protects HEI-OC1 cells against OGD/R-induced apoptosis, and this protective effect is associated with reduced activation of the RhoA/ROCK/LIMK1 pathway and Fas system.