Evaluation of Keratinocyte Proliferation and Differentiation in Vitamin D Receptor Knockout Mice

The study investigated the role of the vitamin D receptor (VDR) in keratinocyte function and its link to alopecia in VDR knockout mice. Despite VDR ablation causing several physiological abnormalities, only alopecia persisted after normalizing mineral ion homeostasis. The research found no significant differences in keratinocyte proliferation or differentiation between VDR null and wild-type mice, both in vitro and in vivo. However, VDR null mice exhibited a significant impairment in initiating the hair cycle after depilation, suggesting that alopecia was due to a defect in hair cycle initiation rather than keratinocyte proliferation or differentiation.