Effect of Estrogen on H2O2 Induced Apoptosis of FRTL-5 Cells / 대한내분비학회지

ABSTRACT

BACKGROUND: Understanding the pathways and controlling mechanisms of thyrocyte apoptosis is important for the elucidation of the pathogenesis of goiter or thyroid cancer. A system for evaluating apoptosis, in FRTL-5 cells, triggered by hydrogen peroxide (H2O2), a highly likely apoptogenic signal in physiologic condition, was be set up to see the effects of TSH and estrogen on H2O2-induced apoptosis. METHOD: DNA laddering was used in the optimization process or the conditions of the set-up of system for the evaluation of apoptosis in the FRTL-5 cells. To quantify the apoptosis under the optimized conditions, histone-bound DNA fragments in the cytoplasm were measured by ELISA. RESULTS: 1) The optimized conditions for induction of apoptosis in the FRTL-5 cells by H2O2 were; observation of DNA laddering 18~24 hrs after the addition of 0.3 mM H2O2 to cells maintained in TSH-free, low serum containing media (5H1 or 5H0 media) for 48 hrs. 2) Exposure of the FRTL-5 cells to TSH (1 mU/L) for more than 48 hrs (6H0 media). before the addition of H2O2 significantly decreased the degree of apoptosis, compared to cells maintained under TSH-free conditions (0.98+/-0.21 vs. 2.27 0.11 arbitrary unit, p<0.05), whereas exposure for 24 hrs. did not. 3) Exposure of the FRTL-5 cells to high dose 17- estradiol (1-100 M) significantly decreased the degree of H2O2-induced apoptosis in a dose dependent manner. The addition of serum (1%) blunted the effects of estrogen on H2O2-induced apoptosis, and TSH totally abrogated the estrogen effect.Physiologic doses of estrogen (10~100 nM) showed no suppressive effects on H2O2-induced apoptosis in FRTL-5 cells. CONCLUSION: A system for evaluating apoptosis in FRTL-5 cells triggered by hydrogen peroxide (H2O2), a highly likely apoptogenic signal in physiologic condition, was set up, and found for the first time that high dose estrogen suppressed the H2O2-induced apoptosis in FRTL-5 cells