Impact of Cholesterol Metabolism on H2O2-Induced Oxidative Stress Injury in HepG2 Cells Treated with Fatty Acids.

ABSTRACT

Objective: This study aimed to evaluate the expression of genes involved in cholesterol metabolism and establish their association with oxidative stress (OS). Methods: We employed an in vitro experimental design and cells were divided into six groups C (control), CH (HepG2 + H2O2), CHN (HepG2 + H2O2 + NAC), F (FFA-treated HepG2), FH (FFA-treated HepG2 + H2O2), and FHN (FFA-treated HepG2 + H2O2 + NAC). Cell viability was assessed using the MTT assay, while successful FFA model establishment was confirmed via Oil Red staining and absorbance. Oxidative stress injury was gauged by measuring ROS, SOD activity, and MDA content. RNA transcription and protein expression of cholesterol-related (DHCR24, DHCR7) and oxidative stress-related (NFE2L2, HMOX1) genes were also examined via RT-qPCR and WB. Results: The impact of H2O2 on cell viability exhibited a time-dose-dependent pattern, paralleling the changes in reactive oxygen species (ROS) levels. Compared to the C group, FFA treatment led to an increase in Oil Red absorption and MDA content and decreased SOD activity. However, it did not result in a significant reduction in cell viability. The FH group exhibited reduced cell viability and SOD activity, along with a further elevation in MDA content compared to the F group. Furthermore, the increased SOD activity and decreased MDA content observed in the CH group were effectively reversed following NAC treatment. Such a reversal was not evident between the FHN and FH groups. Compared to the control group, genes associated with cholesterol metabolism and oxidative stress (OS) displayed heightened expression levels in the other treatment groups, with the FHN group showing lower expression levels than the FH group. Notably, changes in the protein expressions of DHCR24, DHCR7, NFE2L2, and HMOX1 were consistent and exhibited correlations. Conclusions: Cholesterol metabolism emerges as a potential mechanism underlying H2O2-induced oxidative stress injury in HepG2 cells treated with FFA.