Epigallocatechin-3-gallate reduces damage to osteoblast-like cells treated with Zoledronic acid

Objective: analyze the effect of zoledronic acid (ZA) alone and in combination with epigallocatechin-3-gallate (EGCG) on human osteoblast cells. Methods: SAOS-2 osteoblastic phenotype cell line treated with different doses (0.01-10 mu M) of ZA or ZA + EGCG underwent cell viability, mineralization, collagen synthesis and cell migration tests. Results: Micromolar (1 and 5 mu M) doses of ZA reduced cell viability (p < 0.001), mineralization (p < 0.001), and collagen synthesis (p < 0.001), while nanomolar doses (0.1 mu M) did not produce any effect. EGCG application partly reversed the inhibition produced by ZA, and even increased mineralization (p < 0.001). Conclusions: the data obtained shows that ZA at micromolar doses produces negative effects on osteoblast at all parameters measured, while at nanomolar levels ZA only affected cell migration and had no other effects on osteoblasts. The addition of EGCG partly reversed the effects produced by ZA, suggesting that this might be a promising preventative measure against BRONJ.