Yao Min, Yaroslavsky Anna, Henry Frank P, Redmond Robert W, Kochevar Irene E
Harvard-MIT Health Sciences Technology Program, Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
Lasers Surg Med. 2010 Feb;42(2):123-31. doi: 10.1002/lsm.20869.
We have developed a light-activated method called photochemical tissue bonding (PTB) for closing wounds using green light and a photosensitizing dye (Rose Bengal-RB) to initiate photochemical crosslinking of wound surface proteins. These studies were designed to determine whether RB causes phototoxicity during closure of skin incisions with PTB.
STUDY DESIGN/MATERIALS AND METHODS: RB phototoxicity was evaluated after sealing incisions in porcine skin ex vivo and rabbit skin in vivo using PTB (1 mM RB, 100 J/cm(2), 532 nm, 0.3 or 0.5 W/cm(2).) Dead cells were identified by pyknotic nuclei and eosinophilic cytoplasm on H&E-stained sections. The influence on RB phototoxicity of penetration of RB into the wound wall (by confocal microscopy), RB concentration in the tissue (by extraction), and fluence of 532 nm reaching depths in skin (calculated from skin optical properties) were investigated.
No significant differences were found in the percent dead cells in PTB-treated and control incisions in porcine skin at 24 hours or in rabbit skin at 2 hours and 3 and 7 days after surgery. RB was retained in a approximately 100 microm wide band next to the wound wall. The mean RB concentration within this band was 0.42+/-0.03 mM. Monte Carlo modeling of light distribution indicated that the fluence rate decreased from the subsurface peak to 0.5 W/cm(2) in the mid-dermis (approximately 350 microm.) In vitro RB phototoxicity to dermal fibroblasts yielded an LD(50) of 0.50+/-0.09 J/cm(2) when the cells contained 0.46 mM RB.
PTB does not cause phototoxicity when used to repair skin wounds even though the RB concentration and 532 nm fluence in the mid-dermis during PTB are much greater than the LD(50) for RB phototoxicity in vitro. These results indicate that phototoxicity is not a concern when using PTB for tissue repair.
我们开发了一种光激活方法，称为光化学组织黏合（PTB），用于闭合伤口，该方法使用绿光和一种光敏染料（孟加拉玫瑰红-RB）来引发伤口表面蛋白质的光化学交联。这些研究旨在确定在用PTB闭合皮肤切口过程中RB是否会引起光毒性。
研究设计/材料与方法：使用PTB（1 mM RB，100 J/cm²，532 nm，0.3或0.5 W/cm²）在体外猪皮肤和体内兔皮肤上密封切口后，评估RB的光毒性。通过苏木精-伊红（H&E）染色切片上的核固缩和嗜酸性细胞质来识别死亡细胞。研究了RB渗透到伤口壁（通过共聚焦显微镜）、组织中RB浓度（通过提取）以及到达皮肤深度的532 nm光通量（根据皮肤光学特性计算）对RB光毒性的影响。
在术后24小时的猪皮肤以及术后2小时、3天和7天的兔皮肤中，PTB处理的切口和对照切口中的死亡细胞百分比没有显著差异。RB保留在伤口壁旁边约100微米宽的带中。该带内RB的平均浓度为0.42±0.03 mM。光分布的蒙特卡罗模拟表明，光通量率从中层真皮（约350微米）的表面下峰值降至0.5 W/cm²。当细胞含有0.46 mM RB时，体外RB对真皮成纤维细胞的光毒性产生半数致死剂量（LD50）为0.50±0.09 J/cm²。
尽管在PTB过程中中层真皮中的RB浓度和532 nm光通量远大于体外RB光毒性的LD50，但当用于修复皮肤伤口时，PTB不会引起光毒性。这些结果表明，使用PTB进行组织修复时无需担心光毒性。
