To induce AA, recipient C3H/HeJ mice (The Jackson Laboratory, Bar Harbor, ME) received a dorsal skin graft from an older C3H/HeJ mouse that had spontaneously developed AA (sent from John P. Sundberg) as previously described.18 (link) Control mice had their own dorsal skin removed and rotated 180 degrees in a sham surgery. Recipient and control C3H/HeJ mice were fed an AIN93 Maintenance diet containing 0 (n=8), 4 (n=7), 12 (n=9), or 28 (n=8) IU vitamin A/g diet (Research Diets, Inc., New Brunswick, NJ) starting two weeks before these mice were grafted. The American Institute of Nutrition (AIN) recommends 4 IU vitamin A/g diet.43 (link) The higher doses were based on vitamin A analysis of the diet fed mice in The Jackson Laboratory production facility, which contained 6–28 IU vitamin A/g diet. Samples from the control sham mice collected 15 weeks post grafting were used in this current study. The Ohio State University IACUC approved all procedures (#2008A0044).