Figure 1: Viability of normal human fibroblasts after UVA irradiation. Normal human fibroblasts were irradiated with UVA at the indicated dosage (J/cm2), and then cell viability was determined using MTT method at the indicated time (h). No change in cell viability under 7.2, 14.4, and 28.8 J/cm2 UVA irradiation was seen in comparison with the sham-irradiated cells ( ; One-way ANOVA) and no difference among the three dosages was seen ( , One-way ANOVA). Decrease in cell viability was observed with the UVA dose over 43.2 J/cm2. Twenty-four hours after 86.4 J/cm2 UVA treatment, cell viability only reached 19.7%, in multiple comparisons with the LSD method. Significant difference among 43.2, 64.8, 86.4, and 108 J/cm2 UVA irradiation was observed.