Effects of Mitomycin C on Cultured Rabbit Osteoblasts

ABSTRACT

PURPOSE: To evaluate the effect of mitomycin C (MMC) on osteotomy site as an adjunctive therapeutic agent during dacryocystorhinostomy, the effect of MMC on cultured rabbit osteoblasts was tested. METHODS: Cultured osteoblasts which was obtained from the iliac crest of rabbits, were treated with MMC (0.2 mg/ml) for 5 or 30 minutes, washed and changed with fresh osteogenic media (Opti-MEM), and then cultured for 24 hours. To observe the effect of MMC dose dependency on cultured osteoblasts, four different concentrations of MMC (0.2 mg/ml, 0.02 mg/ml, 0.002 mg/ml, 0.0002 mg/ml) were applied into the cells and cultured for 24 hours. The effect of fibroblast growth factor (FGF) and transforming growth factor-beta(TGF-beta) on the MMC-treated cells was evaluated. In control group, osteoblasts were cultured in osteogenic media without exposure of MMC for 24 hours. Cell viability was measured using trypan blue staining method. RESULTS: As compared with control group, the growth of osteoblasts was inhibited by MMC (0.2 mg/ml) treatment, 30-minute treatment group demonstrated marked suppression twice as much as 5-minute treatment group. Growth rate of 0.2 mg/ml MMC-treated cells was highly suppressed to 7.7% of control and 0.02 mg/ml MMC-treated cells was inhibited to 15.4% in number. Growth rate of 0.002 mg/ml, 0.0002 mg/ml MMC-treated cells was diminished to 53.8%, 84.6% in number, respectively. Both growth factors had promotive effect on the growth of osteoblasts in 0.002 mg/ml MMC-treated cells, especially in TGF-beta. CONCLUSION: Osteoblasts which were treated for longer time and with higher concentration of MMC showed more severe suppression in growth rate. These results suggest that MMC could have some therapeutic effect on osteotomy site of dacryocystorhinostomy.