Heat-Killed Lactobacillus rhamnosus ATCC 7469 Improved UVB-Induced Photoaging Via Antiwrinkle and Antimelanogenesis Impacts

Exposure of ultraviolet B (UVB) radiation is the main factor from the environment to cause skin photoaging. Lactobacillus rhamnosus ATCC 7469, is a probiotic strain with a good track record for enhancing human health. The present study conducted the impacts of heat-killed L. rhamnosus ATCC 7469 (RL) on photoaging in vitro using mouse skin fibroblast (MSF) cells and human epidermal melanocytes (HEM) exposed to UVB. The results showed that (1) RL-protected UVB-induced cytotoxicity relating to absorb UVB and reduce DNA damage. (2) RL exerted the antiwrinkle impact involved in two aspects. Firstly, RL downregulated MMP-1, 2, 3 expressions associating with MAPK signaling, resulting in the increased the protein expression of COL1A1, further booting type I collagen abundant thereby promoting the antiwrinkle impact in MSF cells. Secondly, RL reduced ROS content, further decreasing oxidative damage relating to Nrf2/Sirt3/SOD2 signaling, thereby promoting the antiwrinkle impact in MSF cells. (3) RL suppressed tyrosinase and TYRP-2 activity and/or levels associating with PKA/CREB/MITF signaling, thereby promoting antimelanogenesis impact in HEM cells. In conclusion, our findings suggest that RL could reduce photoaging caused by UVB via antiwrinkle and antimelanogenesis properties and may be a potential antiphotoaging beneficial component, which is applied in the cosmetic industry.