Expression of p75 neurotrophin receptor during the mineralization of ectomesenchymal stem cells in vitro

Abstract

To investigate the mineralized capacities of ectomesenchymal stem cells (EMSC) from facial process of Sprague Dawley(SD) rat embryo of different age in vitro and the expression of p75 neurotrophin receptor(p75NTR) in this process. The stem cell surface antigens of EMSC from 12.5 d, 15.5 d and 18.5 d SD rat embryonic facial process were tested by flow cytometry technology. E12.5 d EMSC, E15.5 d EMSC and E18.5 d EMSC were incubated under mineralization induction and analysed by alkaline phosphatase(ALP) staining on day 7(d7) and alizarin red staining on day 21(d21). Expression changes of Runt-related transcription factor-2(RUNX2), collagen Ⅰ (Col Ⅰ) and p75NTR in each group were measured using Western blotting and real time(RT)-PCR on day 0(d0), day 7(d7), day 14(d14) and day 21(d21). The expression of the special substances CD29, CD146 and p75NTR in E12.5 d EMSC, E15.5 d EMSC and E18.5 d EMSC were positive, and the expression of CD45 was negative. The expression level of p75NTR in E18.5 d EMSC(84.04%) was much higher than that of E12.5 d EMSC (22.53%) and E15.5 d EMSC(81.43%). The mineralized capacities of E18.5 d EMSC was stronger than that of E12.5 d EMSC and E15.5 d EMSC. The higher expression of RUNX2, Col Ⅰ in E18.5 d EMSC(RUNX2: 1.92±0.20, Col Ⅰ: 1.85±0.66) was found compared with E12.5 d EMSC(RUNX2: 0.38±0.02, Col Ⅰ: 0.33± 0.94) and E15.5 d EMSC(RUNX2: 0.72±0.22, Col Ⅰ: 0.64±0.07) (P<0.05), and p75NTR in the E18.5 d EMSC experimental group(E12.5 d: 0.79±0.23, E15.5 d: 0.84±0.29, E18.5 d: 1.35±0.22) was significantly higher than the in control group(E12.5 d: 0.42±0.12, E15.5 d: 0.43±0.13, E18.5 d: 0.48±0.15)(P<0.05). RT-PCR further proved the results of the Western blotting. p75NTR participated in the mineralization differentiation of EMSC. E18.5 d EMSC had a higher expression of p75NTR and stronger mineralization capacity and was the ideal engineering seed cells.