Effect of Sodium Silicate on Hair Growth in C57BL/6 Mice

A promoting effect of Na₂SiO₃ on hair regrowth was investigated using an animal model of C57BL/6 mice. There were four experimental groups including distilled water (DW, a negative control), 5% minoxidil (MXD, a positive control), 50% Na₂SiO₃, and 100% Na₂SiO₃ solution. The animals were shaved with an electric clipper and then test solutions applied daily with a volume of 0.2 ml per to the dorsal skin of mice for 3 weeks. Body weight and food and water consumption were measured weekly. Photographs of hair regrowth were taken at experimental day 0, 4, 7, 10, 14, 17, and 21. Activities of alkaline phosphatase and γ-glutamyl transpeptidase as well as expressions of growth factors were also determined in the dorsal skin of mice. The animal body weight were not significantly changed among the experimental groups. The MXD and Na₂SiO₃ accelerated hair regrowth compared with DW. The elongation of hair follicles were evidently observed in MXD and 50 or 100% Na₂SiO₃ groups. MXD significantly increased γ-glutamyl transpeptidase at day 14, compared with DW (P less than 0.05). But the activities of alkaline phosphatase and γ-glutamyl transpeptidase were not significantly increased in Na₂SiO₃ groups, compared with DW. The expression of epidermal growth factor was significantly increased in MXD and Na₂SiO₃ groups, compared with DW (P less than 0.05). The expression of vascular endothelial growth factor was not significantly changed by MXD or Na₂SiO₃ treatments. The expression of transforming growth factor (TGF)-β1 was clearly decreased in MXD and Na₂SiO₃ groups, compared with DW. These results indicate that Na₂SiO₃ may have a hair growth-promoting activity and it can be used for treatment of alopecia or boldness in humans.