BACKGROUND:Studies have shown that paeoniflorin functions as replenishing blood and treatment of autoimmune diseases, and bone marrow mesenchymal stem cels also play an important role in the body’s blood and immune function. However, paeoniflorin effects on bone marrow mesenchymal stem cel proliferation and cytokine secretion and expression are rarely reported. OBJECTIVE:To investigate the effect of paeoniflorin on proliferation of bone marrow mesenchymal stem cels and the expression of interleukin-6. METHODS:Human bone marrow mesenchymal stem cels were separated and culturedin vitro by density gradient centrifugation combined with attachment method. The biological characteristics of bone marrow mesenchymal stem cels were identified by flow cytometry and osteogenic/adipogenic induction. The proliferation of bone marrow mesenchymal stem cels under different concentrations of paeoniflorin was detected by MTT method. The mRNA expression and secretion of interleukin-6 in the supernatant of bone marrow mesenchymal stem cels were detected by RT-PCR and ELISA, respectively. RESULTS AND CONCLUSION: Bone marrow mesenchymal stem cels were isolated successfuly and had osteogenic and adipogenic differentiation potential. Compared with the controlgroup, 2 μmol/L and 10 μmol/L paeoniflorin significantly promoted the proliferation of bone marrow mesenchymal stem cels. 10 μmol/L paeoniflorin could significantly decrease the proportion of bone marrow mesenchymal stem cels in G0/G1 phase and increase this proportion in S phase. Compared with the control group, the experimental group could significantly increase the secretion and mRNA expression of interleukin-6 (P < 0.01). It is concluded that paeoniflorin at certain concentrations can obviously promote the proliferation of bone marrow mesenchymal stem cels, and increase the expression and secretion of interleukin-6.