纳米七甲川花菁染料介导的光热/光动力双模式协同治疗病理性瘢痕的实验研究

Our previous research has clarified that three rules are required for an ideal PDT in pathological scar: 1. Therapeutic light resource penetrates into the deeper tissue. 2.Photosensitizer permeates deep inside the scar and pass through the cell membrane afterwards. 3. The activated photosensitizer is capable of producing high amount of reactive oxygen species (ROS). To meet the requirements above, effectively inducing cell apoptosis and, then, the best therapeutic effect can be achieved..Heptamethine cyanine dyes (HCD) belong to organic dye category. Its longest absorption and emission wavelengths lie in 700-900nm, which is tissue penetration beneficial. Meanwhile, it has photothermal and photosensitive properties. HCD derivative-IR-808-is mitochondria-targeted. Under the Photothermal Therapy (PTT)/PDT synergistic working mode, thermal damage and ROS have mutual promoted effects, which enhance the mitochondria toxicity and accelerate cell apoptosis..In this project, HCD loaded nano-ethosomal vesicle, which is developed by mature synthetic technique, is delivered inside the full thickness scar, homogenously and effectively, to facilitate HCD entry-into-fibroblasts. By utilizing the photothermal and photosensitive properties of HCD under the near-infrared light resource, PTT synergizes with PDT in elevating ROS productivity and promoting fibroblast apoptosis. Thus, a new nano-HCD mediated synergistic PDT/PTT dual therapeutic mode in pathological scar is established.

前期研究发现，理想的病理性瘢痕光动力（PDT）治疗必须具备：1.治疗光源波长具有较大的组织穿透深度。2.光敏剂需具有较好的透皮渗透性能。3.光敏剂被激发后在瘢痕内产生较多的活性氧族（ROS）。满足以上三个条件可有效诱导细胞凋亡，并获得最佳治疗效果。.七甲川花菁染料（HCD）是一类有机染料分子，最大吸收波长为组织穿透能力较高的700-900 nm区间，并具有光热(PTT)和光敏特性。其中IR-808衍生物具有线粒体靶向性，在PTT/PDT双模式协同作用下，热损伤和ROS相互促进，可加强线粒体毒性作用和诱导细胞凋亡。.本实验采用成熟的纳米醇脂体合成技术包载HCD分子，将其均匀高效地递送至瘢痕组织全层，促进其进入成纤维细胞。在近红外光源作用下，利用HCD分子光敏和光热特点，PTT和PDT可协同提高ROS产率，促进成纤维细胞凋亡，最终建立纳米HCD介导的病理性瘢痕PTT/PDT协同治疗新模式。

本研究旨在利用醇质体（Ethosome, ES）结构装载七甲川花菁染料（heptamethine cyanine dyes, HCD）分子IR-808，构建吸收波长在近红外（near infrared, NIR）区，集光热和光动力效应于一体的多功能光敏剂分子，通过经皮给药，用于病理性瘢痕的局部光治疗。通过材料形态及理化表征观察ES装载IR-808分子（IR-808-ES）结构的稳定性及光热、光动力转化效率。与体外培养的增生性瘢痕成纤维细胞（hypertrophic scar fibroblasts, HSFs）共培养，观察在HSFs中产生细胞毒物质活性氧簇（reactive oxygen species, ROS）的水平、对细胞的杀伤情况及相关机制。在兔耳瘢痕模型中考察IR-808-ES的经皮渗透能力，研究其透皮机制，同时评估其对增生性瘢痕组织的光治疗效果。为最终构建具有良好透皮性能、光热及光动力转化效率高的新型NIR光敏剂，提高瘢痕光治疗效果提供相关实验依据。本研究首次采用高透皮性能的醇质体结构，装载HCD分子，通过聚集诱导效应（aggregation induced enhancement, AIE），数倍增强IR-808分子的光热及光动力转化效率，通过内源性线粒体途径，协同诱导HSFs凋亡。动物实验表明IR-808-ES分子通过细胞间途径可渗透至致密的瘢痕组织深层，并通过光热、光动力协同治疗，通过诱导HSFs凋亡及促进胶原纤维重排，有效抑制增生性瘢痕。综上所述，本研究通过ES装载IR-808分子，构建全新的具有NIR吸收，集透皮、光热、光动力效应为一体的多功能光敏剂，为病理性瘢痕的治疗提出光热/光动力（photodynamic / photothermal treatment, PTT/PDT）协同治疗新模式。