A novel method for histological examination of hair follicles.

Intact and healthy hair follicles are important for hair growth after hair follicle transplantation. However, effective and practical evaluation methods for the quality of hair follicles are currently lacking. In the present study, we developed a novel fast staining method for histological examination of hair follicles. The whisker follicles from mice were used to explore the staining protocols, and the final protocol for the evaluation of human hair follicles was derived from animal experiments. After extraction, human hair follicles or mouse whisker follicles were permeabilized with 0.3% Triton X-100. Subsequently, hair follicles were processed by either hematoxylin or alkaline phosphatase staining. The integrity and growth state, including the status of hair follicle stem cells and blood vessels of the extracted hair follicles, were clearly identified under a light microscope. Unhealthy hair follicles from donors or hair follicles broken during extraction were easily revealed by this method. Importantly, it took less than half an hour to obtain images of an individual hair follicle. This method is simple and practical for evaluating the quality and status of hair follicles, providing a fast-screening procedure for hair follicle transplantation.