Hairong Li, Yinmei Zhu, Weisong Tang, Biquan Lin, Fangbo Lin
CA attenuates ox-LDL-induced oxidative injury in HAECs, and Nrf2/HO-1 signalling contributes, at least in part, to this response. These in vitro findings support further investigation into whether CA may modulate endothelial redox balance, but they do not establish therapeutic efficacy and require validation in more complex models including primary cells from multiple donors, co-culture systems, and animal studies.
OBJECTIVE: Atherosclerosis is closely associated with endothelial oxidative stress, yet effective pharmacological interventions remain limited. This study investigated whether chebulinic acid (CA) attenuates oxidized low-density lipoprotein (ox-LDL)-induced oxidative injury in human aortic endothelial cells (HAECs) and evaluated the involvement of Nrf2/HO-1 signalling.
METHODS: HAECs were exposed to ox-LDL to establish an in vitro oxidative-injury model and were pretreated with different concentrations of CA. Cell viability, intracellular reactive oxygen species (ROS), nitric oxide (NO), malondialdehyde (MDA), and superoxide dismutase (SOD) were assessed. Nrf2 nuclear translocation was evaluated by immunofluorescence and nuclear/cytoplasmic fractionation, and Nrf2 and HO-1 protein expression was examined by western blotting. Nrf2 involvement was evaluated using the pharmacological inhibitor ML385 and siRNA-mediated Nrf2 knockdown. CA-alone and ML385-alone experiments were performed as basal-effect controls.
RESULTS: Ox-LDL significantly reduced cell viability and NO levels while increasing ROS and MDA accumulation (all P < 0.001). CA treatment reversed these changes in a concentration-dependent manner (P < 0.001). In the supplementary control experiments, CA alone did not significantly alter basal HAEC viability, ROS, NO, MDA, SOD, Nrf2 localisation, or HO-1 expression, whereas ML385 alone did not significantly affect basal viability or oxidative-stress markers. CA promoted Nrf2 nuclear accumulation and increased HO-1 expression. ML385 attenuated the CA-associated changes in Nrf2 nuclear localisation, HO-1 expression, NO, MDA, and SOD, whereas Nrf2 knockdown reduced HO-1 expression and weakened the CA-associated improvements in ROS, NO, MDA, and SOD.
CONCLUSION: CA attenuates ox-LDL-induced oxidative injury in HAECs, and Nrf2/HO-1 signalling contributes, at least in part, to this response. These in vitro findings support further investigation into whether CA may modulate endothelial redox balance, but they do not establish therapeutic efficacy and require validation in more complex models including primary cells from multiple donors, co-culture systems, and animal studies.