- 學位論文
使用活體倍頻顯微術比較分析高加索人與亞洲人間的皮膚內在老化
Comparative analysis of intrinsic skin aging between Caucasian and Asian subjects by in vivo harmonic generation microscopy
摘要
內在皮膚老化是一個皮膚表皮層與真皮層構造與年齡相關變化的不可逆過程。對皮膚醫學和化妝品工業來說，高加索人與亞洲人間的皮膚顯型與作用上的內在老化差異一直是一個有趣的議題。有許多文獻描述種族間的皮膚構造特性差異。然而，大多數的文獻都將分析重點放在角質層，而有些文獻發現某些皮膚特性的個體年齡間差異勝過了種族間的差異。因此，描述更多的皮膚參數與不同種族間的老化差異是近來的需求。本研究調查高加索人與亞洲人間在活體上皮層與真皮乳突區域這些與皮膚內在老化相關的形態改變。與其他顯微術相比，倍頻顯微術是一個最適合研究皮膚老化的工具，因為倍頻效應有分辨表皮層與真皮層的能力。我們將一台波長為1230奈米的飛秒鉻：貴橄欖石雷射作為光源以降低皮膚光衰減。與顯微鏡和雷射掃描系統結合，可以分別獲得次微米和一微米的橫向和縱向解析度和大於300微米的穿透深度。在本研究，我們徵求了31個高加索人受試者以獲取前手臂內側不受光照的活體倍頻顯微影像。結合我們之前亞洲人的分析研究，讓我們得以比較分析高加索人與亞洲人間的內在皮膚老化差異。 在高加索人與亞洲人的比較分析中，高加索人在活性表皮厚度、顆粒層細胞與細胞核大小和細胞核質比、真皮乳突區域之厚度、單位面積所含真皮乳突體積、真皮乳突區域內真皮乳突體積比例、單位面積所含膠原纖維體積和三維叉合指標都有平均而言較大的尺度。高加索人的基底細胞和細胞核大小隨著年齡增加和亞洲人一樣而有變大的趨勢，而高加索人的最大活性表皮厚度、真皮乳突區域之厚度和單位面積所含真皮乳突體積隨著年齡下降與亞洲人有著顯著不同的趨勢。我們認為主要影響高加索人與亞洲人之間外觀上老化的差異是真皮乳突區域相關的參數，而由於基底細胞和細胞核大小在不同種族間的一致性，可以用做評估皮膚內在老化的評分指標。
並列摘要
Intrinsic skin aging is defined as an inalterable process that is associated with the cellular and sub-cellular structural change of epidermis and dermis. Phenotypical and functional differences in the intrinsic skin aging process of individuals between Caucasians and Asians have generated considerable interest in dermatology and cosmetic industry. Some recent works describing racial differences in structural skin aging properties have been reported. However, most of these studies have been focused on stratum corneum and in some other studies interindividual differences in skin quality overwhelm the racial difference. Therefore, there has been a demand for more detailed studies to address various cellular and sub-cellular epidermal/dermal parameters together with age differences among different racial groups. This study investigates the morphological changes related to intrinsic skin aging in the viable epidermis and the dermal papilla zone (DPZ) between Caucasians and Asians. In contrast to other microscopies, harmonic generation microscopy (HGM) is an optimal tool to study skin aging because of the ability to distinguish the epidermis from dermis by different harmonic generation phenomena. A 1230 nm femtosecond chromium-forsterite laser was used for excitation to lessen skin attenuation and a sub-micron and 1-micron resolution in lateral and axial directions and a greater than 300 μm penetrability were previously achieved. In this study, we recruited 31 Caucasian subjects and obtained in vivo HGM images on the sun-protected volar forearm. In combination with our previous results on Asian skin, these studies allow us to comparatively analyze the difference of intrinsic aging between Caucasian and Asian skin. In comparative analysis between Caucasians and Asians, Caucasian subjects have on average larger scale in the viable epidermis thickness, the cellular size, nuclear size and NC ratio of granular cells, the depth of DPZ, the DP volume per unit area, the collagen volume per unit area, the DP volume ratio and the 3D interdigitation index. The cellular and nuclear sizes of basal cells in Caucasians increase with age with the same trend as in Asians, and the maximum viable epidermis thickness, the depth of DPZ and the DP volume per unit area in Caucasians decrease with age with highly significant difference respect to Asians. Our present findings suggest that the primary factor to result in different aging outlook between Caucasians and Asians is the DPZ-related parameters while the cellular, nuclear size of basal cells can serve as scoring indices for intrinsic skin aging due to their consistency between Caucasians and Asians.