Dexamethasone modulation on cultured human retinal pigment epithelial cell

Objective Dexamethasone(DEX) was tested for its ability to modulate human retinal pigment epithelium(hRPE) cell proliferation in cell culture. Methods DEX in different concentrations was added to cultured hRPE cells. The effects were measured with MTT method, 3H thymidine ( 3H TdR) incorporation and flow cytometry. Results DEX increased survival rate and DNA synthesis from 32 mg/L to 320 mg/L under hRPE culture conditions, but paradoxically reduced them at 1 000 mg/L and 3 200 mg/L in dose and time dependent fashion by both MTT assay and 3H TdR incorporation. The cell numbers in S phase and G 2/M phase increased 28.32% at DEX concentration 320 mg/L, in contrast, reduced 41.84% at 1 000 mg/L. Conclusion DEX increased proliferation from 32 mg/L to 320 mg/L, and inhibited proliferation at concentrations greater than 320 mg/L. The inhibiting effect of DEX may happen in S phase and G 2/M phase.