Abstract: Objective To investigate the replicative senescence of human peritoneal mesothelial cells (HPMCs) induced by peritoneal dialysis fluid (PDF) and the intervention effect of bone marrow derived mesenchymalstem cells (MSCs). Methods HPMCs were isolated from peritoneal tissue and cultured in RPMI
1640 medium. PDF was added to the cultured HPMCs. The effects of PDF on senescence of HPMCs were examined by observing number of cell passages, cell proliferation, cell cycle and telomere length. After the addition of MSCs into the culture medium, the effects of MSCs on the senescence of HPMCs were observed, and the related mechanism was evaluated by observing number of cell passages, cell growth rate, cell cycle and telomere length. Results PDF treated HPMCs showed reduction of cell passage number by four to five, suppression of growth rate by 42%, and cease of cell cycle at G1 phase, as compared with the HPMCs cultured in RPMI 1640. Telomere length was shortened (4.35±0.12 kb vs. 5.45±0.10 kb, t=2.228, P=0.000]. Morphological characteristics of senescent cells appeared earlier. The senescence process delayed in HPMCs with the addition of MSCs. Conclusion MSCs may delay cellular senescence of the HPMCs induced by PDF treatment, which provides a new theoretical basis and a treatment method for delaying peritoneal fibrosis and improving longterm efficacy of peritoneal dialysis.

Key words: Peritoneal dialysis fluid, cellular senescence, HPMCs, MSCs