Standardized Extract Shows Cytoprotective Effects in Zoledronic Acid-Treated Fibroblasts and Osteoblasts.

Introduction: Osteonecrosis of the jaw is a condition associated with intraoral ulceration and bone necrosis induced by antiresorptive medications, such as zoledronic acid, a bisphosphonate. Previous data on (H&B.) Verlot wound healing activity prompted the study reported herein on standardized hydro alcoholic extract in vitro cytoprotective activity data on epithelial and osteoblastic cells exposed to zoledronic acid (ZA).

Methods: Primary human gingival fibroblasts and murine pre-osteoblasts were treated with ZA 10 µM together with 5 or 10 µg.mL extract for 24h and 48 h. At both times, cells were submitted to viability assay and caspase 3/7 activation evaluation. Statistical analysis used one-way ANOVA and p=0.05.

Results: In cell viability assay, a drastic damage effect of ZA appeared after 48 h in both epithelial (55.8%) and pre-osteoblastic cells (39.7%). When treated with ZA in combination with extract, cells showed higher viability values: 74.1%-82.3% for fibroblasts and 66% for pre-osteoblasts. Furthermore, the combined treatment presented lower caspase 3/7 activation in fibroblasts and pre-osteoblasts.

Conclusion: At low concentrations, extract showed promising cytoprotective effects against ZA-induced damage actions; however, further in vitro and in vivo studies are required to establish the mechanism of action.