title: Dietary repletion can replenish reduced T cell subset numbers and lymphoid organ weight in zinc-deficient and energy-restricted rats.
abstract: The objective of the present study was to investigate the time course for recovery of lymphoid tissue and T cell subset numbers when Zn-deficient (ZD) or energy-restricted (ER) rats were repleted with control diet; in a second experiment, the link between the stress axis and lymphoid organs was explored. During the deficiency phase, rats were fed a ZD (<1 mg Zn/kg) or control diet (30 mg Zn/kg, nutritionally complete) either as pair-fed controls (ER) or ad libitum-fed controls (CTL) for 3 weeks. During the repletion phase, all rats were fed control diet ad libitum for 3, 7 or 23 d. After the deficiency phase, ZD and ER had lower T cell subset numbers in the thymus compared with CTL, and ZD had reduced T cell subset numbers in the spleen compared with both ER and CTL. T cell subset numbers and lymphoid organ weights recovered from dietary Zn deficiency and energy restriction by 7 d of repletion (except 23 d for thymus weight in ZD), while body weight required more than 23 d for recovery. At the end of the deficiency phase, ZD and ER had higher circulating corticosterone concentrations compared with CTL; plasma TNFalpha was not detectable and there were no differences in plasma haptoglobin, an acute-phase protein. In conclusion, Zn deficiency and energy restriction elevated circulating corticosterone and reduced T cell subset numbers in the thymus and spleen of growing rats. Repletion with a nutritionally complete diet allowed recovery of T cell subset numbers and lymphoid organ weight.
authors.affiliation: Departments of Human Nutritional Sciences, University of Manitoba, Canada.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Hosea
authors.forename: Edward S
authors.initials: ES
authors.lastname: Rector
authors.forename: Carla G
authors.initials: CG
authors.lastname: Taylor
mesh_terms: D000305:Adrenal Cortex Hormones / Q000097:blood; D000818:Animals; D001835:Body Weight; D031204:Caloric Restriction; D003677:Deficiency Diseases / Q000276:immunology*; D004032:Diet; D004435:Eating / Q000276:immunology; D004734:Energy Metabolism / Q000276:immunology; D006242:Haptoglobins / Q000032:analysis; D018655:Lymphocyte Count; D008221:Lymphoid Tissue / Q000276:immunology*; D008297:Male; D009929:Organ Size; D051381:Rats; D017207:Rats, Sprague-Dawley; D013154:Spleen / Q000276:immunology; D013312:Stress, Physiological / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D015032:Zinc / Q000008:administration & dosage / Q000172:deficiency*
chemical_list: D000305:Adrenal Cortex Hormones; D006242:Haptoglobins; D014409:Tumor Necrosis Factor-alpha; D015032:Zinc