title: Effects of FTY720 on rat lymphoid organs.
abstract: BACKGROUND
  In this study, we examined the in vivo effect of FTY720 on rat thymus and spleen.
  
  
  METHODS
  Inbred male Lewis (RT-I(l)) rats, 5-weeks-old, received FTY720 (0.1, 1, or 10 mg/kg) by intramuscular injection into 1 of 4 limbs daily for 7 days. The rats were humanely killed at 1, 3, 5, or 7 days after starting administration of FTY720. The thymus and spleen were obtained for hematoxylin and eosin (HE) as well as immunoperoxidase staining using the antibodies OX8 (CD8), W3/25 (CD4), and OX6 (major histocompatibility complex class II).
  
  
  RESULTS
  HE staining revealed marked atrophy in the cortical region of the thymus among rats administered FTY720 at the dose of 10 mg/kg. The atrophy extended to the whole cortex. On day 7 of administration of FTY 720 (10 mg/kg), the medulla of the thymus showed relative expansion due to cells accumulation. Also, the spleens of FTY720-treated rats revealed an obvious reduction in the T-cell-dependent areas around the central artery. In conclusion, the immunosuppressive effect of FTY720 may be due to an inhibitory effect on T-cell emigration from the thymus to the periphery.
authors.affiliation: Department of Urology, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan. takai@yamaguchi-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Takai
authors.forename: S
authors.initials: S
authors.lastname: Takahara
authors.forename: N
authors.initials: N
authors.lastname: Isoyama
authors.forename: M
authors.initials: M
authors.lastname: Tsuchida
authors.forename: M
authors.initials: M
authors.lastname: Matsumura
authors.forename: Y
authors.initials: Y
authors.lastname: Kishi
authors.forename: K
authors.initials: K
authors.lastname: Uchiyama
authors.forename: K
authors.initials: K
authors.lastname: Naito
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D001284:Atrophy; D000068876:Fingolimod Hydrochloride; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D008221:Lymphoid Tissue / Q000187:drug effects / Q000276:immunology*; D008297:Male; D011409:Propylene Glycols / Q000494:pharmacology*; D051381:Rats; D011917:Rats, Inbred Lew; D013110:Sphingosine / Q000031:analogs & derivatives; D013154:Spleen / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D013950:Thymus Gland / Q000187:drug effects / Q000276:immunology* / Q000473:pathology
chemical_list: D015703:Antigens, CD; D007166:Immunosuppressive Agents; D011409:Propylene Glycols; D000068876:Fingolimod Hydrochloride; D013110:Sphingosine