Osteogenic activity of vanadyl(IV)–ascorbate complex: Evaluation of its mechanism of action

Ana M Cortizo,M Silvina Molinuevo,Daniel A Barrio,Liliana Bruzzone

doi:10.1016/j.biocel.2005.12.007

Ana M Cortizo, M Silvina Molinuevo + Show 2 more

Open Access

https://doi.org/10.1016/j.biocel.2005.12.007

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Abstract

We have previously shown that different vanadium(IV) complexes regulate osteoblastic growth. Since vanadium compounds are accumulated in vivo in bone, they may affect bone turnover. The development of vanadium complexes with different ligands could be an alternative strategy of use in skeletal tissue engineering. In this study, we have investigated the osteogenic properties of a vanadyl(IV)–ascorbate (VOAsc) complex, as well as its possible mechanisms of action, on two osteoblastic cell lines in culture. VOAsc (2.5–25μM) significantly stimulated osteoblastic proliferation (113–125% basal, p<0.01) in UMR106 cells, but not in the MC3T3E1 cell line. VOAsc (5–100μM) dose-dependently stimulated type-I collagen production (107–156% basal) in osteoblasts. After 3 weeks of culture, 5–25μM VOAsc increased the formation of nodules of mineralization in MC3T3E1 cells (7.7–20-fold control, p<0.001). VOAsc (50–100μM) significantly stimulated apoptosis in both cell lines (170–230% basal, p<0.02–0.002), but did not affect reactive oxygen species production. The complex inhibited alkaline and neutral phosphatases from osteoblastic extracts with semi-maximal effect at 10μM doses. VOAsc induced the activation and redistribution of P-ERK in a time- and dose-dependent manner. Inhibitors of the mitogen activated protein kinases (MAPK) pathway (PD98059 and UO126) partially blocked the VOAsc-enhanced osteoblastic proliferation and collagen production. In addition, wortmanin, a PI-3-K inhibitor and type-L channel blocker nifedipine also partially abrogated these effects of VOAsc on osteoblasts. Our in vitro results suggest that this vanadyl(IV)–ascorbate complex could be a useful pharmacological tool for bone tissue regeneration.

Highlights

In order to investigate the effect of VOAsc on cell proliferation and differentiation, both osteoblast-like cell lines (MC3T3E1 and UMR106) were used
To examine the effect of VOAsc on osteoblast differentiation, alkaline phosphatase activity and type-I collagen production were evaluated in both cell lines
We investigated the effect of a previously synthesized and characterized vanadium(IV) complex with ascorbic acid obtained at pH 7.0

Summary

Introduction

Highly vascularised tissue with a unique capacity to heal and remodel throughout life (Salgado, Coutinho, & Reis, 2004). The integrity of the skeleton requires the coordinated regulation and activity of bone-forming cells (osteoblasts) and boneresorbing cells (osteoclasts). These cells are involved in the turnover of bone matrix components: hydroxyapatite. The maintenance of a balance between formation and resorption results from opposing effects on the life span of osteoblasts and osteoclasts, including anti-apoptotic effects on the former and pro-apoptotic effect on the latter cell type (Kousteni et al, 2002; Manolagas, 2000). Disbalance in skeletal cell activity can result in severe bone alterations. Agents used commonly for the treatment of metabolic bone diseases, such as parathyroid hormone and bisphosphonates, exert their beneficial effects on bone by regulating the rate of birth of new osteoblasts or osteoclasts or their apoptosis (Plotkin et al, 1999)

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