Effect of different doses of UVA1 phototherapy on skin photodamage in immune-contact sensitized mice

ObjectiveTo evaluate the degree of skin injury caused by different doses of UVA1 irradiation and balance the relationship between UVA1 phototherapy and photodamage, aiming to maximize the therapeutic benefits. MethodsDifferent doses of UVA1 irradiation were simulated to treat immune-contact sensitized mouse models. The degree of skin photodamage during treatment was observed and photodamage-related indexes were detected. ResultsWith the increase of dose and irradiation times, the proportion of mice with black spots on the skin was significantly higher than that of mice without sunburn or erythema （both P < 0.05）. However, there were no significant changes in skin thickness and histomorphology compared with the non-photosensitized mouse model group. The detection of malondialdehyde （MDA） and reduced glutathione （GSH） on the skin showed that the increase of doses and irradiation times would cause the increase of MDA content （P < 0.05）； For GSH, the increase of doses would cause the decrease of GSH content （P < 0.05）；and the irradiation time exerted no effect （P > 0.05）. ConclusionsDifferent doses of UVA1 phototherapy can cause skin photodamage, which is aggravated with the increase of dose and frequency. However, this photodamage is mild in the short term, especially with low-dose UVA1 irradiation. The balance between phototherapy effect and photodamage needs to be considered for moderate- and high-dose UVA1 irradiation.