The In Vitro Effects of Bupivacaine on Cartilage-forming Tumor Cells

Introduction: Bupivacaine is a commonly used local anesthetic that has been shown to be cytotoxic to articular chondrocytes and various tumor cells. This study evaluates the in vitro effects of bupivacaine on cartilaginous tumor cells. Methods: Multiple different cartilaginous tumors were evaluated, including enchondromas, chondroblastomas, a low-grade chondrosarcoma, which were harvested from patients during tumor resection, and a grade-II chondrosarcoma SW1535 (ATCC HTB-94). The tumor cells were treated with 0.25% and 0.5% bupivacaine at various times points, and the result was compared with that of untreated tumor cells. Tumor cell viability and apoptosis were evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay and flow cytometry. Results: The tumors were analyzed in groups according to their pathologic diagnosis. Increasing periods of exposure to bupivacaine decreased the cell viability in all tumor samples. The cytotoxicity of 0.5% bupivacaine was significantly greater than that of 0.25% bupivacaine in all tumor cells tested. Discussion: At clinically relevant concentrations, in vitro exposure to bupivacaine caused a decrease in cellular viability and an increase in the induction of apoptosis in a dose- and time-dependent manner in each of the tumor cells evaluated in this study.