Research Paper Volume 15, Issue 22 pp 12702—12722

Figure 7. Aged EVs impact epidermal reconstruction in a 3D model. Young or old keratinocytes were used to reconstruct cultured epidermis in a 3D organotypic model. Reconstructed epidermis obtained with aged keratinocytes were treated with EVs obtained from young keratinocytes culture medium. Conversely, reconstructed epidermis obtained with young keratinocytes were treated with EVs obtained from old keratinocytes culture medium. Representative sections stained with hematoxylin/eosin/safranin are shown in (A) (Scale bar = 100 μm). The epidermal thickness in 3D culture corresponding to old keratinocytes treated with young EVs are shown in (B) (Abbreviation: ns: non-significant in Student t-test). The epidermal thickness in 3D culture corresponding to young keratinocytes treated with old EVs are shown in (C) (^***p-value < 0.001. Student t-test). The reconstructed epidermis sections were stained with Ki67. Representative images of the various conditions are shown in (D) The number of Ki-67 positive cells per μm is shown in (E) The 2 first bars in left correspond to 3D cultures from aged cells whereas the bars in right correspond to 3D cultures with young cells (Abbreviation: ns: non-significant in a Student t-test).