Alterations in telomere length and mitochondrial DNA copy number in human lymphocytes on short-term exposure to moderate hypoxia. (2020)

• Record Type: Journal Article
• Authors: Alam, Mohammad Rizwan; Kim, Dae-Kwang
• Is Part Of: Toxicology reports. Volume 7(2020)
• Page Start: 1443
• Page End: 1447
• Publication Date: 2020
• Subjects: Moderate hypoxia -- Human lymphocyte -- Telomere length elongation -- Mitochondrial DNA copy number -- Genomic instability; Toxicology -- Periodicals; Clinical toxicology -- Periodicals; Drug-Related Side Effects and Adverse Reactions; Hazardous Substances; Poisoning; Toxicology; Electronic journals; Periodicals; Periodicals; 571.9505
• DOI: 10.1016/j.toxrep.2020.10.011
• Languages: English
• ISSNs: 2214-7500

Abstract

Graphical abstract: Highlights: Exposure to moderate hypoxia for 24 h significantly increased telomere length. Telomere elongation is related to the duration of hypoxia exposure. Mitochondrial DNA copy number was unaffected by hypoxia exposure. Mitochondrial DNA copy number is a more stable marker than telomere length alteration under hypoxia. Abstract: Hypoxia is related to a variety of diseases, such as cardiovascular and inflammatory diseases and various cancers. Telomere length (TL) may vary according to the hypoxia level and cell types. To the best of our knowledge, no study has investigated the effect of moderate hypoxia on TL and mitochondrial DNA copy number (mtDNAcn) in human lymphocytes. Therefore, in this study, we analyzed the effect of moderate hypoxia on TL in correlation with mtDNAcn. This study included 32 healthy male nonsmoker's subjects; in this cohort, we had previously studied sister chromatid exchange and microsatellite instability. Blood samples from each subject were divided into three groups: a control group and two experimental groups exposed to moderate hypoxia for 12 or 24 h. Relative TL and mtDNAcn were measured by a quantitative real-time polymerase chain reaction. The TL in the control group did not significantly differ from that in the experimental group subjected to hypoxia for 12 h; however, the TL in the 24 h hypoxia–treated experimental group was significantly higher than that in the control group. The correlation between TL and mtDNAcn was not statistically significant in the two hypoxic states. The increase in TL was observed on exposure to hypoxia for 24 h and not for 12 h; thus, the findings suggest that telomere elongation is related to hypoxia exposure duration. The mtDNAcn in the two experimental groups did not significantly differ from that in the control group. These observations suggest that mtDNAcn alterations show more genetic stability than TL alterations. To the best of our knowledge, this is the first in vitro study on human lymphocytes reporting an increase in TL and no alteration in mtDNAcn after short-time exposure to moderate hypoxia.