皱纹的产生以及皮肤因老化而变得粗糙被认为缘于皮肤最深层的真皮组织的变化。由于这层组织逐渐纤维化,从而导致皮肤弹性降低。但美国纽约州渡茨坦市克拉克森大学的伊戈尔·索科洛夫小组研究显示,在真皮层之上的上皮细胞可能也会产生此类变化。当研究人员将原子力显微镜尖端戳入在实验皿中培养的人体上皮细胞以测量其硬度时,发现通过多次分裂的细胞硬度是“较年轻”细胞的2～10倍。他们认为硬度的增强缘于细胞骨 The generation of wrinkles and the roughening of the skin due to aging are thought to be due to changes in the deepest dermal tissue of the skin. As this layer of tissue gradually fibrosis, resulting in reduced skin elasticity. However, studies conducted by the Igor Sokolov group at Clarkson University in Dutsdam, New York, USA, suggest that epithelial cells above the dermis may also produce such changes. When the researchers poked the tip of an atomic force microscope into the human epithelial cells cultured in a laboratory dish to measure its hardness, it was found that the cells that were divided by multiple times were 2 to 10 times as hard as younger cells. They believe that the increase in hardness is due to cell bone.