Abstract: Objective To investigate the effect of astragalus polysaccharides on human periodontal ligament stem cells ( PDLSCs) and the related mechanisms by regulating microRNA-375 (miR-375). Methods In this study, human PDLSCs were isolated and cultured in vitro. Cells were treated with 0, 40, 100, 400 μg / mL astragalus polysaccharide for 48 h. Cells in the astragalus polysaccharides + anti-miR-NC group and astragalus polysaccharides + anti-miR-375 group were transfected with anti-miR-NC and anti-miR-375 respectively, and treated with 400 μg / mL astragalus polysaccharides for 48 h. Alkaline phosphatase (ALP) activity were measured and the proliferation of PDLSCs was assayed by using methylthiazolyldiphenyl-tetrazolium bromide (MTT). The expression levels of Runt-related transcription factor 2 (Runx-2), osteopontin (OPN) and osteocalcin (OCN) were detected by Western blotting. The expression level of miR-375 was detected by real-time quantitative polymerase chain reaction (qRT-PCR). Results Astragalus polysaccharide can promote the expression of miR-375 [ (1. 54 ±0. 16, 1. 92 ±0. 20, 2. 54 ±0. 22) of the astragalus polysaccharide groups vs. (0. 92 ±0. 07) of the control group] . Astragalus polysaccharide treatment promoted the proliferation of PDLSCs, the A values were (0. 46 ±0. 05, 0. 58 ±0. 07, 0. 72 ± 0. 06) of the astragalus polysaccharide groups vs. (0. 35 ±0. 04) of the control group for 48 h treatment, and (0. 53 ±0. 05, 0. 69 ±0. 07, 0. 84 ±0. 09) of the astragalus polysaccharide groups vs. (0. 40 ±0. 03) of the control group for 72 h. The values for ALP activity were (0. 73 ±0. 08, 0. 84 ±0. 07, 1. 03±0. 09) of the astragalus polysaccharide groupsvs. (0. 32 ±0. 03) of the control group. Treatment with various concentrations of astragalus polysaccharide also up-regulated the expression of Runx-2 [ (1. 32 ±0. 11, 1. 51 ±0. 14, 1. 83 ±0. 17) vs. (0. 92 ±0. 07)], OCN [ (1. 47±0. 13, 1. 65 ±0. 16, 1. 89±0. 19) vs. (0. 99±0. 06)], OPN [ (1. 53 ±0. 15, 1. 72 ± 0. 16, 1. 99 ±0. 20) vs. (1. 00±0. 04)] . The expression level of miR-375, cell proliferation, ALP activity, and the expression levels of Runx-2, OCN, OPN of astragalus polysaccharide + anti-miR-375 group were significantly lower than that of the astragalus polysaccharide + anti-miR-NC group. Conclusion Astragalus polysaccharide can promote the proliferation and osteogenic differentiation of human periodontal ligament stem cells, and its mechanism may be related to miR-375.

Key words: astragalus polysaccharide, miR-375, human periodontal ligament stem cells; proliferation, osteogenic differentiation