β-Nicotinamide Mononucleotide Promotes Cell Proliferation and Hair Growth by Reducing Oxidative Stress

β-Nicotinamide mononucleotide (NMN) has shown promising effects on intestinal health, and it is extensively applied as an anti-aging and Alzheimer's disease therapeutic, due to its medicinal properties. The effects of NMN on the growth of mouse hair were observed after hair removal. The results indicated that NMN can reverse the state of hair follicle atrophy, hair thinning, and hair sparsity induced by dihydrotestosterone (DHT), compared to that of minoxidil. In addition, the action mechanisms of NMN promoting hair growth in cultured human dermal papilla cells (HDPCs) treated with DHT were investigated in detail. The incubation of HDPCs with DHT led to a decrease in cell viability and the release of inflammatory mediators, including interleukin-6 (IL-6), interleukin-1Beta (IL-1β) and tumor necrosis factor Alpha (TNF-α). It was found that NMN can significantly lower the release of inflammatory factors induced by DHT in HDPCs. HDPCs cells are protected from oxidative stress damage by NMN, which inhibits the NF-κB p65 inflammatory signaling pathway. Moreover, the levels of androgen receptor (AR), dickkopf-1 (DKK-1), and β-catenin in the HDPCs were assessed using PCR, indicating that NMN can significantly enhance the expression of VEGF, reduced IL-6 levels and suppress the expression of AR and DKK-1, and notably increase β-catenin expression in DHT-induced HDPCs.