Nutrition disorders and immunologic parameters: study of the thymus in growing rats.
OBJECTIVE
We studied the effect of a low-quality dietary protein on cellular proliferation and maturation in the thymus of growing rats over time.


METHODS
After weaning Wistar rats were fed a diet containing 6.5 g/100 g of corn flour for 6, 10, 18, and 45 d (M groups). For comparison, other rats were fed a diet containing 6.5 g/100 g of casein (Cas groups), and well-nourished age-matched control rats were fed a commercial laboratory diet (C groups). Food intake, body weight, thymus weight, total number of thymocytes, and the percentages of CD43(+) and Thy1(+) thymocyte phenotypic antigen determinants were measured.


RESULTS
M versus Cas and C groups showed significant differences (P < 0.01) in body and thymus weights after 6 d of feeding, and the total number of thymocytes and the percentages of CD43(+) and Thy1(+) were significantly lower after 10 d of feeding. The results indicated that consuming a cereal diet for short or long periods causes thymus atrophy in growing rats, with significant reductions in the total number of T-cells concomitant with increases in the number of immature thymocytes.


CONCLUSIONS
The data showed that, in addition to low-protein concentration, low-quality dietary protein is a limiting factor in certain steps of cellular intrathymic pathways, probably related to the requirement of specific amino acids for optimal immune response.
Pallaro
A N
AN
Department of Nutrition, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina. apallaro@ffyb.uba.ar
Roux
M E
ME
Slobodianik
N H
NH
D000818:Animals; D015703:Antigens, CD; D015415:Biomarkers; D001835:Body Weight / Q000276:immunology; D002364:Caseins / Q000008:administration & dosage / Q000592:standards; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000592:standards; D004435:Eating; D005260:Female; D051917:Leukosialin; D018655:Lymphocyte Count; D008297:Male; D009748:Nutrition Disorders / Q000276:immunology* / Q000503:physiopathology; D009753:Nutritive Value; D009929:Organ Size / Q000276:immunology; D010641:Phenotype; D011488:Protein Deficiency / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D012795:Sialoglycoproteins / Q000032:analysis / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D018800:Thy-1 Antigens / Q000032:analysis / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000254:growth & development* / Q000276:immunology / Q000473:pathology; D003313:Zea mays / Q000592:standards
D015703:Antigens, CD; D015415:Biomarkers; D002364:Caseins; D004044:Dietary Proteins; D051917:Leukosialin; D012795:Sialoglycoproteins; C497864:Spn protein, rat; D018800:Thy-1 Antigens