Puerarin and zinc additively prevent mandibular bone loss through inhibiting osteoclastogenesis in ovariectomized rats

Abstract

Puerarin and zinc play a key role in preventing osteoporotic-related bone loss. Previous research on puerarin or zinc mainly focused on the antiosteoporotic effects of long bone. However, it is obscure for puerarin or zinc to prevent mandibular osteoporosis. Here, we explore the effects on additive coadministration of puerarin and zinc on preventing mandibular bone loss in ovariectomized rats, and evaluate the underlying mechanisms ex vivo. Rats were ovariectomized and administrated puerarin, zinc or both. After 12 weeks, bone mineral density (BMD) and histomorphometry of mandibles were measured by micro-CT. The mechanical properties were determined using a threepoint bending test. Then, osteogenic differentiation of primary bone marrow stromal cells (BMSCs) and osteoclastogenesis of bone marrow mononuclear were performed ex vivo. The culture supernatant and serum level of bone biochemical markers including osteoprotegerin (OPG), osteopontin (OPN), receptor activator of nuclear factor (NF)-κB ligand (RANKL), and tartrate-resistant acid phosphatase (TRAP) were detected by ELISA. Culture supernatant and serum levels of calcium were measured using a Plasma Emission Spectrometer. One-way ANOVA was used for statistical analyses. The results showed that administration of puerarin plus zinc prevented the decrease in mandibular BMD and bone morphometrical parameters more effectively than single use of puerarin or zinc (p<0.05), which was similar to the biomechanical tests (p<0.05). Furthermore, puerarin and zinc additively up-regulated OPG, OPN protein levels, Ca ion level and down-regulated RANKL, TRAP protein levels. In conclusion, puerarin and zinc additively prevent mandibular bone loss through inhibiting osteoclastogenesis in ovariectomized rats, which will shed more light on the potential use of puerarin and zinc in the prevention/treatment of oral bone loss clinically.