The Effects of Negative Pressure Therapy on Hair Growth of Mouse Models.

Negative pressure therapy (NPT) has been shown to facilitate wound healing and promote hair growth in a porcine model. However, there is a paucity of research on the impact of negative pressure on hair growth in murine models. Despite the ability of nude mice to develop hair follicles, the hair they produce is often flawed due to genetically induced keratin disorders, rendering them a pertinent animal model for assessing hair regeneration. Therefore, this study aims to investigate the effects of negative pressure on hair follicle growth in a nude mouse model. To achieve this, a customized external tissue expansion device (ETED) was developed to apply negative pressure to the dorsum of nude mice. The mice were subjected to several treatment courses consisting of 15 and 30 min of continuous negative pressure at 10 mmHg, which were repeated five and ten times every other day until sacrifice. Dorsal skin samples were subsequently extracted from the suction and non-suction areas. The sections were stained with various antibodies to assess the expression of SOX-9, LHX-2, Keratin-15, β-catenin, CD31, and VEGF-A, and a TUNEL assay was used to analyze cell apoptosis. The results showed that the number of hair follicles and angiogenesis were significantly higher in the suction area (SA) than in the non-suction area (NSA) in all groups. Moreover, mice that received negative pressure therapy for 15 min 10 times had a higher hair follicle density than the other three groups. Immunofluorescence staining for LHX-2 and Keratin 15 further validated the results of these findings. In conclusion, this study demonstrated that negative pressure effectively promotes hair follicle growth and angiogenesis in nude mice through SOX-9 and LHX-2-mediated follicular regeneration and β-catenin-mediated hair follicle morphogenesis.  .