Aim: 

Mesenchymal stem cells (MSCs) are multipotent cells in the bone marrow stromal line, known for their potential to differentiate into several types of cells. The aim of this study was to verify the effects of dexamethasone (DEX) or estradiol (E₂) on proliferation and differentiation of rat bone marrow MSCs in culture, evaluating by western blotting and immunocitochemical analysis of some specific neural proliferative and differentiative markers.

Methods: 

MSCs were harvested from bone marrow of femurs of 4 to 8 month-old rats. Cytofluorimetric analysis revealed that MSCs were negative for CD45, CD34 and positive for CD90, CD105.

After 24 h starvation period, MSC cultures were treated for 48 h with DEX 10^-9 M or E₂ 5 × 10^-9 M. Qualitative and quantitative analysis were performed by immunocitochemical and western blot analysis respectively

for nestin, neurofilament, b-tubulin and MAP-kinase.

Results: 

Our results show an enhancement of the above mentioned neural markers and MAP-Kinase in MSCs cultures treated with DEX. E₂-treatment increased MAP-Kinase and b-tubulin expression, but it decreased nestin and neurofilament expression.

Conclusion: 

Collectively, our results indicate that DEX induces an up regulation of some neural protein expression indicating an its possible role played on differentiation of these MSCs to neural line. In addition, it shows an involvement on signal transduction patways. On the contrary, E₂ treatment induces up and down modulation of nestin, neurofilament, b-tubulin and MAP-kinase expression.