[Investigation on disturbing of adipocytic differentiation of rBMSCs by loaded titanium particles]

Our previous investigations demonstrated that varying sizes of loaded titanium particles could inhibit proliferaion, adhension and osteoblastic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs). The present study aims to validate the hypothesis that particled-shaped wear debris from prosthetic implants influence the adipocytic differentiation of rBMSCs. The effects of different sizes of loaded titanium particles (6.9 microm, 2.7 microm and 0.9 microm) on the adipocytic differentiation of rBMSCs were studied by observing lipid droplet formation, assaying the expression of lipoprotein lipase (LPL) mRNA by RT-PCR and Triglycerides (TG) secretion. The loaded titanium particles were found to influence adipogenesis of rBMSCs, but had different effects, depending upon particle size, concentration and loading time duration. 2.7 microm and 0.9 microm titanium particles promoted lipid droplet formation, LPL mRNA expression and TG secretion, while at a higher concentration of titanium particles and a longer loading duration, 6.9 microm titanium particles gradually inhibited adipogenic differentiation of rBMSCs. Three sizes of loading titanium particles obviously disturbed the adipocytic differentiation capability of rBMSCs: the smaller particles promoted but the larger inhibited the adipogenic differentiation of rBMSCs.