The abnormal DNA damage response may result in genomic instability, which is one of the pivotal factors of tumorigenesis. The genomic stability is decreased in senescent cells. Recent studies about telomere, telomerase, oncogenes and cancer suppressor genes indicate that cell aging is closely linked with cancer.OBJECTIVE:
Using an oxidative damage model to determine whether the abnormal DNA damage response is the direct cause of genomic instability in senescent cells.METHODS:
Bone marrow mesenchymal stem cells were cultured and identified by flow cytometry. Cell aging was detected using senescence-associated β-galactosidase. Cell proliferation was determined using BrdU incorporation test. Human mesenchymal stem cell aging model was established in vitro. Cell Counting Kit-8 was used to observe cell survival, and DCFH-DA fluorescent probe was used to detect intracellular reactive oxygen species. Then the cell damage repair ability was detected by single cell gel electrophoresis assay.RESULTS AND CONCLUSION:
Human mesenchymal stem cells were found to be senescent after long term culture, implied by increased number of senescence-associated β-galactosidase-positive cells and decreased BrdU incorporation. The growth curve showed that the survival rate of senescent mesenchymal stem cells was lower than that of young mesenchymal stem cells after hydrogen peroxide treatment. Furthermore, supporting evidence from the reactive oxygen species detection and single cell gel electrophoresis assay demonstrates that senescent mesenchymal stem cells underwent more serious DNA damage and required longer repair time. All these results imply that senescent mesenchymal stem cells are more sensitive to hydrogen peroxide injury than their young counterparts.RESULTS AND CONCLUSION:
Zhang Y, Yu J, Zhang Y, Shi JZ, Huang YQ, Yang J. Aging reduces oxidative damage repair ability of mesenchymal stem cells. Zhongguo Zuzhi Gongcheng Yanjiu. 2013;17(10):1801-1808.