The proliferation and viability of human keratinocytes were analyzed after treatment with different concentrations of homogenized placental extract (H-PE) or acid-hydrolyzed placental extract (A-PE).

<p>Human keratinocytes (HaCaT) were incubated for 24 hr in the presence of different concentrations of (A) H-PE or A-PE; (B) H-PE or A-PE under 0.5 mM H₂O₂; and (C) H-PE or A-PE under 1 mM H₂O₂. Cell viability in the presence of H-PE or A-PE under oxidative stress was measured by the MTT assay. The data are presented as the percentage of control (non-treated cells) and the mean ± SD of at least three independent experiments. *p<0.05.