Removal of Trsp provokes thymus atrophy. (A-D) Appearance of thymus from Trsp^fl/del and Trsp^fl/del:Mx1-Cre mice on an Nrf2^+/+ or Nrf2^–/– background at 4 weeks after the final pI-pC injection. Orange dot lines indicate thymus. (E) Thymus/body weight ratios of Nrf2^+/+:Trsp^fl/del (n = 6), Nrf2^+/+:Trsp^fl/del:Mx1-Cre (n = 5), Nrf2^–/–:Trsp^fl/del (n = 5), and Nrf2^–/–:Trsp^fl/del:Mx1-Cre (n = 7; *P < .05). (F) Flow cytometric analysis of T cells (CD4⁺/CD8⁺) in thymus of Trsp^fl/del and Trsp^fl/del:Mx1-Cre mice on an Nrf2^+/+ or Nrf2^–/– background. Representative data are presented from more than 3 independent experiments. (G-V) Histological examination of thymus from Trsp^fl/del and Trsp^fl/del:Mx1-Cre mice on an Nrf2^+/+ or Nrf2^–/– background with hematoxylin and eosin staining (G-N) or Oil Red O staining (O-V). Scale bars correspond to 200 μm (G-J and O-R) and 25 μm (K-N, S-V), respectively. C, cortex; M, medulla.