Characterization of Hair Follicles in Hirosaki Hairless Rats with Deletion of Basic Hair Keratin Genes: Enlarged Medulla, Loss of Cuticle, and Long Catagen

March 2009 in “ Hirosaki University Repository for Academic Resources (Hirosaki University) ”

Miki Akita, Naoki Nanashima, Toshiyuki Yamada, Hajime Nakano, Takeshi Shimizu, Fan Yang, Shigeki Tsuchida

hair follicles Hirosaki hairless rats basic hair keratin genes catagen phase hair medulla inner root sheath hair cuticle hair cortex Kb25 hypotrichosis keratin fusion gene hair loss hair thinning hair structure hair growth phase hair model

TLDR Hirosaki hairless rats have sparse, twisted hair due to missing hair keratin genes.

The study on Hirosaki hairless rats, which had deletions in basic hair keratin genes, revealed significant alterations in hair structure, including an enlarged medulla, loss of the cuticle, and an extended catagen phase. An 80-kb deletion on chromosome 7q36, affecting genes Kb21, Kb23, Kb26, and Krt2-25, led to sparse and twisted hairs, with hair follicles entering the catagen phase earlier than in normal rats. These findings highlighted the role of keratin genes in hair development and provided a model for studying hair disorders like hypotrichosis, emphasizing the genetic factors that influence hair follicle formation and pathology.

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