Pearl extract protects HaCaT cells from UV radiation-induced apoptosis through mitochondrial pathway regulation

Background: Previous studies have demonstrated that pearl extract (PE) promotes wound healing and skin whitening. However, it remains unclear whether PE can inhibit ultraviolet (UV)-photodamage in HaCaT cells. In this study, an in vitro photoaging cell model was established to observe the effect of PE on UV-induced damage and the apoptosis of HaCaT cells. The aim of this study was to provide a reference for the future development of natural sunscreens. Results: PE concentrations of 0.1 and 1 μg/mL were considered the most effective and safe concentrations. Compared to that in the control group, superoxide dismutase and glutathione peroxidase activity in the photoaging group was significantly reduced, whereas malondialdehyde and reactive oxygen species content, along with tumour necrosis factor-alpha (TNF-α) and interleukin (IL)-10 mRNA and protein levels, were markedly increased. In contrast, Bcl-2 protein expression was significantly decreased, whereas caspase-3, caspase-9, and Bax protein expression levels were significantly increased. Compared to that in the photoaging group, HaCaT cell proliferation was significantly increased in the PE group. Both PE concentrations significantly increased superoxide dismutase and glutathione peroxidase activity in cells, reduced malondialdehyde and reactive oxygen species content, decreased TNF-α and IL-10 mRNA expression in cells, and reduced TNF-α and IL-10 protein levels in the supernatant. Additionally, Bcl-2 protein expression levels were significantly increased, whereas caspase-3, caspase-9, and Bax protein expression levels were significantly reduced by PE treatment. Conclusions: PE can inhibit UV-induced apoptosis by inhibiting mitochondria-mediated apoptosis and regulating TNF-α and IL-10 expression.