FIG. 1.

In vitro tumor-killing efficacy of HF-LPLI (200 mW/cm² at 10 min) through ROS generation. (A) ROS generation and mitochondrial depolarization. Representative sequential images of ASTC-a-1 cells double stained with H₂DCFDA, SE, and TMRM were acquired after PDT or HF-LPLI treatment. (B, C) FACS analysis of ROS generation and ΔΨm changes. The temporal profiles of the DCF (B) and Rh123 (C) intensities in ASTC-a-1 cells were acquired 1 h after HF-LPLI treatment. Cells were pre-cultured with NAC (250 μM) 1 h before HF-LPLI. (D) Cell death analysis was performed by annexin V-FITC/PI double staining in A549 cells 3 h and 10 h after PDT and HF-LPLI treatment, respectively. Cells were pre-cultured with DHA (250 μM) 1 h before HF-LPLI. (E–G) Detection of the effect of oxidative damage on lipid, protein, and DNA. Levels of MDA (E), protein carbonyls (F), and 8-OHdG (G) in three different cell lines ASTC-a-1, A549, and EMT6 were detected 6 h after HF-LPLI treatment. Cells were pre-cultured with NAC (250 μM) 1 h before HF-LPLI. The data represent the mean±SD (n=5). *P<0.05 versus control. 8-OHdG, 8-hydroxydeoxyguanosine; A549, human lung adenocarcinoma cell line; ASTC-a-1, human lung adenocarcinoma cell line; DCF, 2′,7′-dichlorofluorescein; DHA, dehydroascorbic acid; EMT6, mouse mammary tumor cell line; FACS, flow cytometry; FITC, fluorescein isothiocyanate; H₂DCFDA, SE, 2′,7′-dichlorodihydrofluorescein diacetate, succinimidyl ester; HF-LPLI, high fluence low-power laser irradiation; MDA, malondialdehyde; NAC, N-acetyl-l-cysteine; PDT, photodynamic therapy; PI, propidium iodide; Rh123, rhodamine 123; ROS, reactive oxygen species; SD, standard deviation; TMRM, tetramethylrhodamine methyl ester; ΔΨm, mitochondrial transmembrane potential. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars