Effect of Thermoablation with pH Change on Giant Cell Tumor of Bone: An In Vitro Study

Abstract

Objective: To evaluate the effect of pH on the apoptosis and necrosis rate of giant cell tumor of bone (GCTB) cells during thermoablation. Materials and Methods: GCTB tissues were collected from 15 patients. Cells were incubated at 25 ºC , 37 ºC, 45 ºC, and 50 ºC, with the variation of the pH at 4.7, 5.6, 6.5, 7.4, 8.3, and 9.2 for 20 minutes (in triplicate for each condition). The effect of thermoablation and pH variation on GCTB cells death was evaluated by staining with Annexin V-FITC and propidium iodide solution after 3 days of incubation. The fluorescence intensity was evaluated by flow cytometry to evaluate the percentage of tumor cells death. Results: Thermoablation alone increased the percentage of tumor cells death. However, when combined with an increase in pH, the percentage of GCTB cells death increased more. Conversely, lowering the pH did not increase the tumor cells death compared with thermoablation treatment alone, while changing the pH alone had only a low effect on increasing the percentage of GCTB cells death. Conclusion: Thermoablation the temperature between 37 ºC and 45 ºC plus a pH level slightly higher than physiologic pH (between 7.4 and 8.3) for 20 minutes increased GCTB cell death. However, determining the optimum condition to kill tumor cells while causing minimal harm to normal cells requires more study.