Study On The Protect Effect Of Estrogen Against Serum Deprivation On RS Cells

Serum deprivation (SD)-caused harm in Marrow stromal cells (MSCs) after transplantation into an ischemic heart has been the issue at the center stage in cardiology. MSCs were recently shown to be enhanced by estrogens in protective function by cytokine regulation and growth factor production. Thus, demonstration molecular mechanism of estrogen protection effect against SD to improve micro-environment in ischemia has been one of the core subjects in cardio-regenerative medicine.RS cells are characterized by their extremely small size, rapid rate of replication, and enhanced potential for multilineage differentiation. Moreover, they can be distinguished from more mature cells in the same cultures by a series of surface epitopes and expressed proteins. Therefore, the results raise the possibility that RS cells may have the greatest potential for long-term engraftment and differentiation in vivo. In the present study, we have therefore investigated RS cells as target subjects to study the effects of SD and estrogen protection, to accelerate and improve their progress in clinic application. Also, we have provided and discussed the possible pathways estrogen worked.In the present study, two subpopulations of rMSCs, mMSCs and RS cells were taken as subjects separately, to demonstrate estrogen protection effects against SD. The innovative point of this research was to use estrogen as the protective agent in ischemic environment, and to focus on RS cells to explore its biological characters.Here we incubated rMSCs with initial plating density from 3-1000 cells/cm2 for 7-14 days. First, cell morphology was observed by microscope and cell culture images management. Second, cell growth kinetics was analyzed by growth curve determined. Third, cell growth potential was estimated by CFU tests. Results showed that 10 cells/cm2 was the optimal plating density when cultured for 7-10 days. Proliferation potentials of rMSCs reduced when plating densities arisen. Besides, mMSC repressed proliferation of RS cells by both contact inhibition and cell factors secretion.After harvesting rMSC cultures enriched with RS cells, we demonstrated that rMSCs treated by 10nM 17 beta-estradiol (E2) have a greater capacity to survive under conditions of ischemia, measured by detecting changes in cellular morphology and phosphatidylserine exposure. We also compared two subpopulation of cultures of MSCs: Small and rapidly self-renewing cells (RS cells) and the large, more mature and slowly replicating cells (mMSCs). The viability and the apoptosis percentage of cultures enriched for RS cells were 2.75-fold and 1.38-fold higher respectively. Also, RS cells retained greater proliferation ability after 12h of SD as the viability. Moreover, rMSCs were arrested in S phase under SD conditions, and ER reduced this percentage by 5.8%.