Puerarin Enhances Bone Mass by Promoting Osteoblastogenesis and Slightly Lowering Bone Marrow Adiposity in Ovariectomized Rats

Abstract

We investigated the effect of puerarin on bone mass and marrow adiposity in ovariectomy (OVX)-induced osteoporosis. The rats were divided into four groups: control; OVX; OVX+estradiol (OVX-E); and OVX+puerarin treatment (OVX-GE). In vivo, bone mineral density (BMD) and histomorphometry were measured under microCT. The mechanical properties of tibia were obtained in 3-point bending test. Plasma osteocalcin and adiponectin were determined using enzyme-linked immunosorbent assay (ELISA). Alkaline phosphatase (ALP) were measured using biochemical methods. In vitro, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Oil Red O staining were used to compare osteoblast proliferation and adipocyte differentiation, respectively. Osteocalcin and adiponectin in culture supernatants were determined using ELISA. The results showed that puerarin significantly enhanced bone volume density and trabecular number compared with OVX and OVX-E groups (p<0.05, p<0.05, respectively). Puerarin increased energy to ultimate load, plasma osteocalcin and ALP (p<0.01). However, BMD in OVX-GE group was less than that in control (p<0.01) and OVX-E groups (p<0.05). The culture supernatants from OVX-GE group showed increased osteocalcin compared with those from OVX (p<0.01) and OVX-E groups (p<0.05). Puerarin lowered adiponectin in culture supernatant compared with supernatant from OVX group and inhibited the increase in adipocytes caused by OVX (p<0.01). However, the amount of lipids did not differ between OVX-GE and OVX groups. These findings suggest that puerarin likely enhances bone formation by stimulating the proliferation and differentiation of osteoblasts while slightly inhibiting the adipotic differentiation.