重度低氧对小鼠肝脏成纤维细胞生长和线粒体功能的影响OA

To investigate the mechanisms of hypoxia-induced cellular injury,mouse liver fibroblasts were exposed to three representative high-altitude hypoxic conditions,including 11％O2 representing mild hypoxia,5％O2 representing moderate hypoxia,and 1％O2 representing severe hypoxia.Cell viability was assessed using the MTT assay,ultrastructural changes were examined by transmission electron microscopy,intracellular oxidative stress was evaluated by ROS fluorescent probing,and mitochondrial membrane potential was assessed by JC-1 staining.In addition,RT-qPCR and Western blot were performed to determine the transcriptional and protein expression levels of genes related to mitochondrial function and apoptosis.Compared with the normoxic control group(21％O2),11％O2 treatment caused no obvious changes in cell density or morphology,and cell viability showed a time-dependent increasing trend without statistical significance(P＞0.05),whereas 5％and 1％O2 treatments induced marked morphological alterations.Under 1％O2 exposure,cell viability did not differ significantly from the normoxic control at 24 h(P＞0.05)but declined sharply at 48 h and 72 h(P＜0.001),reaching the lowest level at 72 h.This reduction was accompanied by increased ROS accumulation,loss of mitochondrial membrane potential,and pronounced mitochondrial ultrastructural damage,including mitochondrial swelling and cristae disruption.Furthermore,after 72 h of 1％O2 treatment,the Bax/Bcl-2 ratio was significantly increased at both mRNA and protein levels(P＜0.05),while the mitochondrial fission-related gene Drp1 was significantly downregulated at both transcriptional and protein levels(P＜0.05).Collectively,severe hypoxia at 1％O2 impaired mitochondrial integrity and function,promoted apoptosis,and reduced cell viability,indicating that profound hypoxia induces hypoxia-associated injury in mouse liver fibroblasts.