應用雙光子顯微術觀察油酸對皮膚滲透動態傳輸之影響

Abstract

我們使用雙光子螢光顯微術來觀察裸鼠皮膚的角質層在240分鐘之內經由油酸增強的跨皮膚滲透過程。硫化若丹明 B (SRB)被使用作為模擬極性分子的跨皮膚滲透。一種對極性敏感的染劑，若丹，被使用來監控角質層內極性環境的變化。極化的程度可以透過總體極化量(GP)參數值(-1<= GP <=1)來決定。其中高GP值對應非極性環境而低GP則對應極性環境。在滲透過程中所使用的溶劑為磷酸鹽緩衝溶液與乙醇以1:2體積所形成的混合液，此為控制組溶液，實驗組溶液則加入額外3%體積的油酸。 我們的結果顯示出在沒有油酸加入的情況下，極性分子較容易經由角質細胞間質區域滲透而非極性分子比較容易穿過角質細胞內部滲透。油酸的加入不只增加SRB分子滲透速率，也增加達到穩定態滲透的速率。再者，油酸的加入導致在皮膚表面以下10微米的距離內的GP值的增加的現象說明了加入油酸不只改善極性分子(如SRB或水分子)的滲透連帶的溶液中其他有較高GP值的成分如乙醇，DMSO的滲透亦被增強。油酸的加入同時也使得角質內部角質細胞間質與角質細胞內部的SRB強度與GP值的分布比較均勻，以及角質內部角質細胞間質與角質細胞內部之間的滲透增強。

We used two-photon fluorescence microscopy to observe 240 minutes of the oleic acid-enhanced transdermal permeation process in the stratum corneum (SC) of nude mouse skin. Sulforhodamine B (SRB) was used to simulate the transdermal delivery of polar molecules. A polarity-sensitive probe, Laurdan, was used to monitor the environmental polarity in SC. The degree of polarity is determined by the general polarization (GP) parameter (-1<= GP <=1) with a high GP value for non-polar environment and a low GP value for polar environment. The solvent used for the permeating process was a mixture of phosphate buffered saline and ethanol in a 1:2 ratio by volume for the control group. For the experimental group, an additional 3% by volume of oleic acid was added. Our results show that without the addition of oleic acid, polar molecules preferentially permeate through the intercellular regions while non-polar molecules preferentially permeate through the intracellular regions. The addition of oleic acid greatly increased not only the permeation rate of SRB, but also the rate that the steady state permeation rate is reached. Furthermore, the addition of oleic acid leads to an increase in the GP value within 10 um of skin surface suggesting that oleic acid improves the permeation of not only polar molecules (SRB, water) but also other higher GP values components in the solution such as ethanol and DMSO (dimethyl sulfoxide). The addition of oleic acid results in a more homogeneous distribution of SRB intensity and GP values in both intercellular and non-intercellular region of SC, and an enhancement of the permeation between intercellular region and intracellular region.