Laboratory of Food Science and Human Health, College of Food Science and Engineering, Ocean University of China, Qingdao, China.
Laboratory of Food Science and Human Health, College of Food Science and Engineering, Ocean University of China, Qingdao, China; Innovation Center for Marine Drug Screening and Evaluation, Marine Biomedical Research Institute of Qingdao, 266071, China.
Photodiagnosis Photodyn Ther. 2019 Jun;26:244-251. doi: 10.1016/j.pdpdt.2019.04.002. Epub 2019 Apr 3.
The objective of this study was to evaluate the bactericidal effect of curcumin (CUR)-mediated photodynamic inactivation (PDI) against Escherichia coli DH5α in vitro and in oysters, then further investigate the edible security of PDI-treated oysters based on cellular toxicological methods. First, DH5α cells were irradiated by a 470 nm LED light source with an energy density of 3.6 J/cm. Colony forming units (CFU) were counted and the viability of DH5α cells was calculated after treatment with CUR-mediated PDI. Intracellular production of reactive oxygen species (ROS) was studied by measuring the fluorescence of 2, 7-dichlorofluorescein (DCF) using a flow cytometry. Membrane permeability was measured using confocal laser scanning microscopy (CLSM) with propidium iodide (PI) staining. After that, the bactericidal effect of CUR-mediated PDI was evaluated in oysters which were pre-contaminated with DH5α cells. Finally, cellular toxicology of PDI-treated oysters was evaluated through morphological observation, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, DNA ladder assay, and nuclear staining. Results showed that the viability of DH5α was significantly decreased in a CUR concentration-dependent manner and resulted in an approximately 3.5-log reduction at the concentration of 20 μM. After treatment with CUR-mediated PDI (20 μM, 3.6 J/cm), the ROS level in DH5α cells and the membrane permeability markedly increased. Our data demonstrated that CUR-mediated PDI had a good decontamination effect against DH5α contaminated in oysters. After incubation with PDI-treated oysters, fibroblasts L929 cell morphology, MTT absorbance and cell apoptosis had no obvious changes. Our findings preliminarily demonstrated that CUR-mediated PDI-treated oysters had no cytotoxicity to fibroblasts.
本研究旨在评估姜黄素（CUR）介导的光动力灭活（PDI）对体外大肠杆菌 DH5α和牡蛎的杀菌效果，然后进一步通过细胞毒理学方法研究 PDI 处理牡蛎的食用安全性。首先，将 DH5α 细胞用 470nm LED 光源照射，能量密度为 3.6J/cm。用 CUR 介导的 PDI 处理后，通过计数集落形成单位（CFU）并计算 DH5α 细胞的存活率。通过用流式细胞术测量 2,7-二氯荧光素（DCF）的荧光来研究细胞内活性氧（ROS）的产生。用碘化丙啶（PI）染色的共聚焦激光扫描显微镜（CLSM）测量膜通透性。之后，评估了 CUR 介导的 PDI 在预先污染 DH5α 细胞的牡蛎中的杀菌效果。最后，通过形态观察、3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐（MTT）测定、DNA 梯状电泳和核染色评估 PDI 处理牡蛎的细胞毒性。结果表明，DH5α 的活力随 CUR 浓度呈依赖性降低，在 20μM 浓度下，活力降低约 3.5 个对数级。用 CUR 介导的 PDI（20μM，3.6J/cm）处理后，DH5α 细胞内 ROS 水平和膜通透性明显增加。我们的数据表明，CUR 介导的 PDI 对牡蛎中污染的 DH5α 具有良好的去污效果。用 PDI 处理的牡蛎孵育后，成纤维细胞 L929 细胞形态、MTT 吸光度和细胞凋亡无明显变化。我们的研究结果初步表明，CUR 介导的 PDI 处理的牡蛎对成纤维细胞没有细胞毒性。
