Preparation of Psoralen

Psoralen with purity over 99% by HPLC analysis (cat. P8399) was obtained from Sigma (St. Louis, MO), and its chemical structure is shown in Figure 1A. Psoralen was dissolved in dimethyl sulfoxide (DMSO) and then diluted with culture medium to yield final concentration of 0.01, 0.05, 0.1, and 0.5 μmol/L. The final concentration of DMSO in the solutions applied to cells was 0.2% (v/v). HTR8/SVneo cells in the control group were exposed only to RPMI 1640 medium supplemented with 0.2% DMSO. These concentrations of psoralen for HTR-8/SVneo cells were determined in the pre-experiment. The entire drug dispensing process was completed in a sterile environment.

Psoralen enhances HTR-8/SVneo cell viability. (A) Chemical structure of psoralen. Cell viability (B) and LDH release (C) of HTR-8/SVneo cells after exposure to different concentrations (0, 0.01, 0.05, 0.1, and 0.5 μmol/L) of psoralen for 0, 24, 48, and 72 h. Values are mean ± SD. Experiments were performed in triplicate and repeated three times. ^* p < 0.05 vs. 0 μmol/L; ^# p < 0.05 vs. 0.01 μmol/L; ^† p < 0.05 vs. 0.05 μmol/L; ^‡ p < 0.05 vs. 0.1 μmol/L.