2021 年 44 巻 2 号 p. 225-231
The dermis is mainly constructed by type I collagen fibers, which provide mechanical strength to the skin by building a frame-like structure, and by elastic fibers, which provide elasticity to respond to movements of the skin. The depletion of collagen fibers and the disappearance of oxytalan fibers, which are a type of elastic fiber, are characteristic changes in photoaged skin. Prostaglandin E2 (PGE2) is one of the chemical mediators involved in inflammation and is responsible for sunburn. Furthermore, it has been reported that PGE2 attenuates the production of collagen and the expression of elastic fiber-related factors in fibroblasts. Tranexamic acid (TXA), which is an anti-inflammatory medicine that inhibits plasmin, reduces the level of PGE2 secreted following UV exposure or after inflammatory stimulation. However, few reports have verified TXA as an anti-skin aging agent. In this study, we examined the potential of TXA as an anti-skin aging agent using repetitively UVA-irradiated fibroblasts as a model for fibroblasts located in chronically sun-exposed dermis. Repetitively UVA-irradiated fibroblasts had higher secretion levels of PGE2. In addition, fibroblasts repetitively irradiated with UVA or treated with PGE2 produced disrupted collagen and fibrillin-1 fibers. Treatment with TXA improved the formation of both types of fibers by repetitively UVA-irradiated fibroblasts by restoring the expression of fiber-related proteins at the mRNA and protein levels. Thus, these results demonstrate that TXA has potential as an anti-photoaging agent.
