Effect Of Uric Acid On Expression Of BMP-2 In Bone Marrow Mesenchymal Stem Cells During Osteogenic Differentiation

Objective: To observe effect of uric acid(UA) on expression of bone morphogenetic protein-2(BMP-2) in differentiation process from human bone marrow mesenchymal stem cells(h BMSCs) to osteoblasts in vitro.Methods: The h BMSCs were isolated and cultured using the whole bone marrow adherence method. The Passage 3 h BMSCs were divided into 5 groups: blank control group(adding complete medium) and osteogenic induction group(adding osteoblast inducing media and 0 mmol/L 0.2 mmol/L 0.4 mmol/L 0.8 mmol/L UA in complete medium). After the 14 days of induction, cell morphology was observed under the inverted microscope. Osteogenic ability was identified by the alkaline phosphatase(ALP) activity assay and the alizarin red stain. The BMP-2 m RNA expression was detected by reverse transcription PCR(RT-PCR).Results: The Passage 3 cells were single long-spindle in shape and gradually formed a whirlpool-shaped arrangement. After the induction, the majority cells were from long-spindle to irregular cube in shape, and gradually became paving stone or formed nodules. Among all groups, the cells in 0.8 mmol/L UA induction medium formed the most nodules. After the 14 days of induction, calcium nodules in the blank control group were negtive, however the calcium nodules were dyed orange in osteogenic induction group. The result showed the h BMSCs were induced into osteoblasts successfully. The ALP activity enhanced gradually with the increase of intervention time and UA concentration(P<0.05). The RT-PCR results showed the BMP-2 m RNA was hardly detected in control group. In induced group, the m RNA expression of BMP-2 was evaluated with the increase of UA concentrations(P<0.05).Conclusions: The UA can upregulate the expression of the BMP-2 m RNA during the osteogenic differentiation of the h BMSCs.