1.Association between specific-frequency vibration and ferroptosis-related indicators in vascular endothelial cells
Siheng WU ; Hongyu YANG ; Kanshou ZHOU ; Fanfei ZENG ; Qingsong CHEN ; Yun XIA
Journal of Environmental and Occupational Medicine 2026;43(3):278-285
Background Prolonged vibration exposure can lead to vascular endothelial cell dysfunction and cellular injury. However, research on the association between vibration and ferroptosis in vascular endothelial cells remains insufficient. Objective To explore whether occupational vibration exposure is associated with alterations in serum markers related to ferroptosis in patients with hand-arm vibration disease (HAVD), and to further investigate, through in vitro cell experiments, whether vibration exposure may induce ferroptosis in vascular endothelial cells. Methods ①A judgmental sampling method was employed to select 50 workers with HAVD (the HAVD group), 50 vibration-exposed workers without HAVD (the vibration exposure group), and 50 non–hand-transmitted vibration-exposed workers (the control group). Serum iron levels, malondialdehyde (MDA) content, and superoxide dismutase (SOD) levels were measured using serum iron assay kits, MDA detection kits, and SOD detection kits, respectively. One-way analysis of variance and binary logistic regression analysis were performed to examine the relationships between these indicators and HAVD. ②Human umbilical vein endothelial cells (HUVEC) were divided into a vibration group and a control group. The vibration group was subjected to vibration at 120 Hz with an acceleration of 6.5 m·s−2 and further subdivided into four subgroups: 1 d 2 h, 1 d 4 h, 2 d 2 h, and 2 d 4 h. The control group was treated identically except for vibration exposure. Cellular iron (Fe2+) content and reduced glutathione (GSH) levels in HUVEC were measured using ferrous iron colorimetric assay kits and GSH colorimetric assay kits, respectively, to assess the effects of different vibration exposure schedules. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to detect the mRNA expression levels of ferroptosis-related genes, including acyl-CoA synthetase long-chain family member 4 (ACSL4), tumor suppressor protein P53 (P53), ferritin heavy chain 1 (FTH1), and glutathione peroxidase 4 (GPX4). Western blot analysis was conducted to determine the protein expression levels of ferroptosis-related markers in HUVEC. Results ①Compared with the control group, the patients in the HAVD group showed increased serum iron and MDA levels, along with decreased SOD levels (P<0.05). The logistic regression analysis indicated that elevated serum iron levels were significantly associated with an increased risk of HAVD (OR=4.034; 95%CI: 2.063, 7.887), and elevated MDA levels were also associated with an increased risk of HAVD (OR=1.523; 95%CI: 1.026, 1.936). ②Compared with the control group, increased intracellular Fe2+ content and decreased GSH content were observed in HUVECs in the 1 d 4 h and 2 d 4 h vibration subgroups (P<0.05). The RT-qPCR results showed that, compared with the control group, vibration exposures of 1 d 4 h and 2 d 4 h significantly upregulated the expression of ACSL4 and P53 (P<0.05), whereas the mRNA expression levels of GPX4 and FTH1 were downregulated in all vibration-exposed endothelial cells (P<0.05). The Western blot results revealed that, compared with the control group, the vibration exposure schedules of 1 d 2 h and 1 d 4 h significantly upregulated the protein expression levels of ACSL4 and P53 (P<0.05), while the vibration exposure schedules of 1 d 4 h, 2 d 2 h, and 2 d 4 h significantly downregulated the protein expression levels of FTH1 and GPX4 (P<0.05). Conclusion Occupational vibration exposure is associated with alterations in iron metabolism and oxidative stress status in workers with HAVD. The in vitro experiments further demonstrates that vibration stimulation induces intracellular iron accumulation and reduces antioxidant capacity in vascular endothelial cells, accompanied by dysregulated expression of ferroptosis-related molecules. These findings suggest that ferroptosis may play a role in vibration-induced vascular injury and the pathogenesis of HAVD.
2.Changes in iron content, lipid peroxidation, and ferroptosis-related gene expression in vascular endothelial cells in vitro induced by vibration
Siheng WU ; Qingsong CHEN ; Yingshan ZENG ; Yun XIA ; Hongyu YANG
Journal of Environmental and Occupational Medicine 2024;41(5):560-566
Background Vascular endothelial injury is an important pathogenic step of vibration-induced hand arm vibration disease (HAVD), and long-term vibration exposure can lead to vascular endothelial cell dysfunction and cell damage. Cell ferroptosis may be one of the important mechanisms of vibration-induced vascular endothelial cell injury and HAVD. Objective To explore whether vibration can induce changes in ferroptosis-related indicators in vascular endothelial cells in vitro. Methods Human umbilical vein endothelial cells (HUVEC) were divided into four vibrationgroups and two control groups. The vibration groups were exposed to an vibration setting of 125 Hz, 6.5 m·s−2 frequency band and for different durations: 1 d 2 h (total 1 d, 2 h per day), 1 d 4 h (total 1 d, 4 h per day), 2 d 2 h (total 2 d, 2 h per day), and 2 d 4 h (total 2 d, 4 h per day), respectively. All control groups were treated the same as the experimental groups except no vibration exposure. When the cells were 80% confluent, the control groups and the corresponding experimental groups were harvested at the same time. The effects of subgroup treatments on iron, reduced glutathione (GSH), and malondialdehyde (MDA) in HUVEC were detected with a cell ferrous colorimetric test kit, a reduced GSH colorimetric test kit, and a trace MDA test kit, respectively. Real-time quantitative polymerase chain reaction (RT-PCR) was used to detect the mRNA expressions of ferroptosis-related genes acyl-CoA synthetase long chain family member 4 (ACSL4), tumor protein 53 (P53), recombinant human ferritin heavy chain (FTH1), and glutathione peroxidase 4 (GPX4). Western blot (WB) was used to detect the expression levels of ferroptosis-related proteins in HUVEC. Results Compared with the control groups, the vibration induced an increase in the iron content of HUVEC with a dose-response trend. Compared with the control groups, the reduced GSH content of HUVEC in the vibration group decreased with the increase of vibration time and frequency, and there was a dose-response trend. Compared with the control groups, the intracellular MDA content of HUVEC in the 1 d 2 h, 1 d 4 h, and 2 d 4 h vibration groups increased, and the MDA content in the 1 d 2 h and 1 d 4 h vibration group increased with time. The RT-PCR results showed that the mRNA expression levels of ACSL4 and P53 in the 1 d 4 h group increased compared with the 1 d 2 h group. Compared with the 2 d control group, the mRNA expression levels of ACSL4 in the 2 d 2 h vibration group and the 2 d 4 h vibration group increased, and the mRNA expression level of P53 in the 2 d 4 h vibration group increased. Compared with the 1 d control group, the mRNA expression levels of FTH1 and GPX4 in endothelial cells in the vibration 1 d 2 h group decreased. The WB results showed that compared with the control groups, the expression level of ferroptosis-related protein ACSL4 in endothelial cells increased in the vibration 1 d 2 h group; the expression levels of P53 in the 1 d 2 h and 2 d 4 h vibration groups increased; the expression levels of GPX4 decreased in the 1 d 4 h and 2 d 2 h vibration group, and the decrease was more obvious in the 2 d 2 h vibration group than in the 1 d 2 h vibration group; the above differences were statistically significant (P<0.05). Conclusion Vibration induces an increase in iron content, a decrease in GSH, and an increase in MDA in vascular endothelial cells in vitro, as well as mRNA and protein expressions of ferroptosis-related genes ACSL4, P53, FTH1, and GPX4.

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