BackgroundThe restoration of damaged meniscus has always been a challenge due to its limited healing capacity. Recently, bone marrow-derived mesenchymal stem cells (BMSCs) provide a promising alternative to repair meniscal defects. However, BMSCs are not ideal chondroprogenitor cells for meniscus repair because they have a high propensity for cartilage hypertrophy and bone formation. Our hypothesis is that mesenchymal stem cells (MSCs) reside in meniscus maintain specific traits distinct from others which may be more conducive to meniscus regeneration.MethodsMSCs were isolated from bone marrow and menisci of the rabbits. The similarities and differences between BMSCs and MMSCs were investigated in vitro by a cell culture model, ex vivo by a rabbit meniscus defect model and in vivo by a nude rat implantation model using histochemistry, immunocytochemistry, qRT-PCR and western blotting.ResultsOur data showed that two types of MSCs have universal stem cell characteristics including clonogenicity, multi-potency and self-renewal capacity. They both express stem cell markers including SSEA-4, Nanog, nucleostemin, strol-1, CD44 and CD90.However, MMSCs differed from BMSCs. MMSC colonies were much smaller and grew more slowly than BMSC colonies. Moreover, fewer MMSCs expressed CD34 than BMSCs. Finally, MMSCs always appeared a pronounced tendency to chondrogenic differentiation while BMSCs exhibited significantly greater osteogenic potential, whatever in vitro and in vivo.ConclusionsThis study shows the similarities and differences between MMSCs and BMSCs for the first time. MMSCs are a promising source of mesenchymal stem cells in repairing meniscus defect.Electronic supplementary materialThe online version of this article (doi:10.1186/s12891-015-0511-8) contains supplementary material, which is available to authorized users.

The solubility data of probenecid in 12 different organic solvents including methanol, methyl acetate, ethanol, ethyl acetate, n-propanol, n-butanol, butyl acetate, n-pentanol, isopropanol, isobutanol, acetone, and methyl tert-butyl ether was measured using the gravimetric method over the temperatures range from 283.15 to 323.15 K at 0.1 MPa. The acetone had much higher solubility to probenecid than to other solvents. Three models, including the modified Apelblat equation, the van’t Hoff model, and the nonrandom two-liquid (NRTL) model, were applied to correlate the measured solubility data. The correlation results were evaluated by the average relative deviation (ARD). All of the ARD values were less than 4.522%, which indicated that the three models have a satisfactory correlation. The thermodynamic properties of mixing of probenecid in 12 pure organic solvents including the enthalpy of mixing, Gibbs energy of mixing, and entropy of mixing were calculated by the NRTL model using the correlation results.

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