Nitrate Promoting Hair Growth Through Enhancing Wnt/β-catenin and Downregulating TGF-β/Samd/BMP signaling pathway in C57BL/6 Mice

Nitrate found widely distributed in vegetables and fruits. It has been proved to have many physiological functions through nitrate-nitrite-NO pathway, such as attenuate oxidative stress, enhance the skeletal muscle and tone skin vascular. But the function of nitrate in regulating hair growth is unclear. Here, we evaluated potential roles of nitrate on hair growth and its mechanisms by in vivo models. Mice treated with 10mM nitrate supplementation significantly promoting hair growth, along with an increase in the number of hair follicles and thickness of dermis. We further demonstrated that Wnt3a and β-catenin were highly expressed in the nitrate-treated groups, while the expression of TGF-β was attenuated. Moreover, nitrate also increased the expression levels of growth factors (Fgf, Igf-1, and Vegf). Our data indicated that nitrate supplementation could effectively accelerate hair regrowth through activating the Wnt/β-catenin and inhibiting TGF-β1/Smad/BMP signaling pathway. Therefore, these findings provide support for a potential therapeutic role of nitrate in preventing and treating alopecia.