Abstract:

Objective To observe the effect of ultraviolet irradiation comparising 95% ultraviolet A （UVA） and 5% ultraviolet B （UVB） on the proliferation of human epidermal keratinocytes （HEKs）, in hope to offer a basis for the construction of a photodamaged skin model induced by sunlight. Methods HEKs were isolated from foreskin tissue and cultured in vitro. After several passages, the HEKs were irradiated with different doses （0, 2.5, 5, 10, 20, 30, 40, 60 J/cm2 ） of UV comprising 95% UVA and 5% UVB. Methyl thiazolyl tetrazolium （MTT） assay was used to evaluate cell viability after 24 hours of additional culture. SPSS １7.0 software was used to calculate the median lethal dose（LD50） of ultraviolet radiation in HEKs. Results The proliferation of HEKs was inhibited by 0, 1.03%, 6.60%, 17.28%, 31.28%, 49.59%, 59.67% and 70.99% respectively after irradiation with UV of 0, 2.5, 5, 10, 20, 30, 40 and 60 J/cm2. A significant inhibition of cell proliferation was observed in HEKs irradiated with UV at a dose of no lower than 10 J/cm2 compared with unirradiated HEKs （F = 62.11, P < 0.05）. The LD50 of UV in HEKs was 31.31 J/cm2. Conclusions Aas the dose of UV irradiation increases, the proliferative activity of HEKs decreases, with the LD50 of UV being 31.31 J/cm2.