Steroid regulation of proliferation and osteogenic differentiation of bone marrow stromal cells: a gender difference

Abstract

Bone marrow mesenchymal stem cells (MSCs) are considered a potential cell source for stem cell-based bone tissue engineering. However, noticeable limitations of insufficient supply and reduction of differentiation potential impact the feasibility of their clinical application. This study investigated the in vitro function of steroids and gender differences on the proliferation and differentiation of rat MSCs. Bone marrow MSCs of age-matched rats were exposed to proliferation and osteogenic differentiation media supplements with various concentrations of 17beta-estradiol (E2) and dexamethasone. Cell proliferation was measured by MTS assay; osteogenic markers and steroid-associated growth factors and receptors were evaluated by ELISA and real-time PCR. The results revealed that supplements of E2 and dexamethasone increase MSC proliferation in a biphasic manner. The optimal dose and interaction of steroids required to improve MSC proliferation effectively varied depending on the gender of donors. Supplementation of E2 effectively improves osteogenic differentiation markers including ALP, osteocalcin and calcium levels for MSCs isolated from both male and female donors. The mRNA of TGF-beta1 and BMP-7 are also up-regulated. However, effective doses to maximally improve osteogenic potentials and growth factors for MSCs are different between male and female donors. The relationship between steroid receptors, osteogenic markers and cytokines are also varied by genders. The outcomes of the present study strongly indicate that steroids potentially function as an effective modulator to improve the capacity of MSCs in bone regeneration. It provides crucial information for improving and optimizing MSCs for future clinical application of bone regeneration.

Figure 1

The effect of E2 and dexamethasone on the proliferation of male (A) and female (B) rat MSCs. N=5, *: p<0.05, **: p<0.01.

Figure 2

Quantitative mRNA of OCN and ALP of MSCs from male (A) and female (B) rats one week after osteogenic differentiation with E2 supplements.

Figure 3

Osteogenic differentiation of MSCs seeded on gelatin sponges. A: ALP activity of MSCs 2 weeks after differentiation; B and C: Calcium contents (B) and OCN (C) of MSCs 4 weeks after differentiation with E2 supplements. N=5; *: p<0.05.

Figure 4

Quantitative mRNA of BMP-7 and TGF-β1 of MSCs from male (A) and female (B) rats one week after osteogenic differentiation with E2 supplements.

Figure 5

Quantitative mRNA of steroid receptors of MSCs one week after osteogenic differentiation with E2 supplements.