Figure 7. Lack of a cytotoxic effect of 17β-estradiol or progesterone on corneal fibroblasts. Cells were incubated for 24 h in MEM in the absence (negative control) or presence of various concentrations of 17β-estradiol or progesterone, after which the culture supernatants were assayed for LDH activity with a colorimetric assay and measurement of absorbance at 490 nm. The amount of LDH released from cells by a cell lysis solution was determined as a positive control. Data are means±SEM from three independent experiments. *p<0.05 versus negative control (Dunnett’s test).