Figure 6. Effect of melatonin on somatic cell proliferation during primordial folliculogenesis in nicotine-exposed ovaries cultured in vitro for 5 days. (A) EdU histochemistry (red) in representative tissue sections of ovaries cultured in vitro from control, 10 μM nicotine and 10 μM nicotine plus 1 μM melatonin. (B) Number of EdU positive somatic cells in each section. The results are presented as mean±SD. All the experiments were repeated at least three times. * P < 0.05; ** P < 0.01.