2022, Vol. 26 ›› Issue (24): 3880-3885

Effect of umbilical cord mesenchymal stem cells on aging thymus epithelial cells

Yang Zailing1, 2, Tian Chuan2, Lyu Guanke1, Pan Hang1, 2, Zhu Xiangqing2, Wang Jinxiang2, Wang Kai2, Ruan Guangping2, He Zhixu3, Shu Liping1, Pan Xinghua2   

Abstract: BACKGROUND: Previous studies have found that the reduced number and dysfunction of thymus epithelial cells are one of the important factors of thymus degeneration. It can lead to thymic cell development, defective proliferation and peripheral T cell dysfunction. The previous research of our team found that mesenchymal stem cells can reverse the structure and function of aging thymus in vivo. The specific mechanism of action is still unclear.
OBJECTIVE: To investigate the effect of umbilical cord mesenchymal stem cells on aging thymus epithelial cells in vitro.
METHODS: The cell viability of the fourth generation thymus epithelial cells was determined by CCK8 assay after treatment with 200 μmol/L H2O2 for 24, 48, 72, and 96 hours, respectively. The 72 hours of 200 μmol/L H2O2 was selected as appropriate time for establishing senescence models. The fourth generation of umbilical cord mesenchymal stem cells was co-cultured with senescent thymic epithelial cells for 48 hours. The changes of senescent cells were detected by β-galactosidase staining. Cell proliferation was detected by immunofluorescence ki-67 staining. Cell cycle changes were analyzed by flow cytometry. Immunohistochemical staining was used to detect the positive expression levels of p53 and p21 proteins. The mRNA expression levels of senescence related genes p21, p53, and pRb were detected by RT-PCR.
RESULTS and CONCLUSION: Compared with the model group, the expression of β-galactosidase in coculture group was decreased; cell proliferation ability was increased; cells in G2 phase were decreased and cells in S phase were increased; immunofluorescence expression of p53 and p21 was increased; mRNA expression of p53 and p21 was decreased and pRb mRNA expression was increased. The results of β-galactosidase expression, cell proliferation ability, p53, p21, and pRb expression in the coculture group were compared with the control group, and the reverse degree was close to the control group. It is concluded that umbilical cord mesenchymal stem cells can regulate the senescence of thymic epithelial cells, promote the proliferation and division of thymic epithelial cells, and reverse the senescence of thymic epithelial cells.
Key words: stem cells, umbilical cord mesenchymal stem cells, thymus, thymus epithelial cells, co-culture, anti-aging, immunity