Induction of the Hair Growth Phase in Postnatal Mice by Localized Transient Expression of Sonic Hedgehog

In 1999, researchers conducted a study on postnatal mice to investigate the role of the Sonic hedgehog (Shh) gene in hair growth. They found that transient, localized overexpression of Shh initiated the anagen growth phase of hair follicles, leading to hair growth. This was achieved by intradermal administration of an adenovirus gene-transfer vector expressing Shh, which resulted in enhanced expression of Shh, Ptc, Gli1, hair-specific keratin, and tyrosinase at the injection site. The study also observed increased hair follicle size, increased dermal and epidermal depth, increased melanogenesis, and increased hair growth. No abnormalities were observed in the skin 6 months after the injection. The study involved 5 mice for each treatment. These findings suggested that transient expression of Shh could potentially activate the hair growth cycle in disease conditions where these functions have been reduced, offering a potential new approach to hair loss therapy. However, this research is 24 years old and may be outdated.