Non-Coherent Near Infrared Radiation Protects Normal Human Dermal Fibroblasts from Solar Ultraviolet Toxicity  Salatiel Menezes  Journal of Investigative Dermatology  Volume 111, Issue 4, Pages 629-633 (October 1998) DOI: 10.1046/j.1523-1747.1998.00338.x Copyright © 1998 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 1 Pre-irradiation with near-IR protects human skin fibroblasts from solar UV cytotoxicity. The cells were exposed (or not) to 30 min of IR radiation (810 kJ per m2), washed two times with HBSS, and irradiated immediately with UVA or UVB. After UV irradiations, the cells were washed again with HBSS and incubated in culture conditions with their original medium for 24 h (UVA) or 72 h (UVB), before counting viable cells. The columns represent the mean ± SD of three independent experiments in triplicate. Student’s paired t test p values < 0.05 are statistically significant. Journal of Investigative Dermatology 1998 111, 629-633DOI: (10.1046/j.1523-1747.1998.00338.x) Copyright © 1998 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 2 The protection induced by IR is a long-lasting phenomenon. After irradiation with IR the cells were irradiated with UVA immediately or after incubation in culture conditions for different periods, as indicated. The columns represent the mean ± SD of three independent experiments in triplicate. Student’s paired t test p values < 0.05 are statistically significant. ns, not significant. Journal of Investigative Dermatology 1998 111, 629-633DOI: (10.1046/j.1523-1747.1998.00338.x) Copyright © 1998 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 3 The intensity of the IR-induced protection is dependent on the number of IR pre-irradiations. The cells were exposed to IR (30 min) one, two, or three times before UVA irradiation. After each IR exposure and before the following irradiation, the cells were incubated under culture conditions for 3 h. The columns represent the mean ± SD of three independent experiments in triplicate. Student’s paired t test p values < 0.05 are statistically significant. ns, not significant. Journal of Investigative Dermatology 1998 111, 629-633DOI: (10.1046/j.1523-1747.1998.00338.x) Copyright © 1998 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 4 Inhibition of mitosis by arabinoside-cytosine does not alter the IR-induced protection. Immediately after irradiations, Ara-C (1 μg per ml, final concentration) was added to the culture medium to block mitosis and the cells incubated for 24 h, in culture conditions, before counting of the viable cells. The columns represent the mean ± SD of three independent experiments in triplicate. Student’s paired t test p values < 0.05 are statistically significant. ns, not significant. Journal of Investigative Dermatology 1998 111, 629-633DOI: (10.1046/j.1523-1747.1998.00338.x) Copyright © 1998 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 5 Inhibition of protein synthesis by cycloheximide does not alter the IR-induced protection. Immediately after irradiations, cycloheximide (10 μg per ml, final concentration) was added to the culture medium to block protein synthesis and the cells were incubated for 24 h, in culture conditions, before counting of the viable cells. The columns represent the mean ± SD of three independent experiments in triplicate. Student’s paired t test p values < 0.05 are statistically significant. ns, not significant. Journal of Investigative Dermatology 1998 111, 629-633DOI: (10.1046/j.1523-1747.1998.00338.x) Copyright © 1998 The Society for Investigative Dermatology, Inc Terms and Conditions