The effects of HSP27 against UVB-induced photoaging in rat skin

Skin photoaging refers to the phenomenon of skin aging or accelerated aging as a result of long-term UV exposure. Ultraviolet radiation can lead to DNA damage, cell apoptosis, cell growth inhibition and carcinogenic effects. Evidence suggests that hsp27 can protect cells from apoptosis induced by various stimuli in vivo and in vitro. However, modulation in hsp27 expression toward skin protection against UVB treatment has not been investigated clearly. In this study, we aimed to investigate the effects of hsp27 against UVB-induced photoaging in rat skin and to explore the underlying mechanisms. In the present study, we identified that the level of hsp27 increased after UVB irradiation induced chronic photoaging rat model. In order to investigate the function of hsp27 in UVB-induced skin photoaging, we used adeno-associated virus (AAV) to specificity reduce the expression of hsp27 in rat skin. In contrast to UVB group, we found that collagen fibers were disorganized and elastic fibers were thickened and twisted in UVB-AAV group. In the UVB-AAV group, reduced hsp27 enhanced the oxidative stress. Aging markers (SA-β-Gal staining and the protein levels of p16, p53, p21) were significantly changed in the hsp27 decreased group. However, in hsp27 deletion group, the expression of antiapoptotic factor bcl-2 was decreased, while the apoptosis factor bax was increased after UVB irradiation. These findings suggested that hsp27 was involved in oxidative stress, aging and apoptosis of skin after UV exposure. Management the expression of hsp27 can be used as a potential intervention method to alleviate UVB-induced skin damage.