T lymphopenia in obese diabetic (db/db) mice is non-selective and thymus independent.
Although C57BL/KsJ db/db mice, an animal model of non-insulin-dependent diabetes mellitus (NIDDM), develop T lymphopenia in association with the progression of NIDDM, the T lymphopenia has not been fully investigated. In this study, to elucidate how and why T lymphopenia develops in db/db mice, T-lymphocyte subsets in spleen and thymus were longitudinally examined by flow cytometry and the effects of thymectomy and dietary restriction on the development of T lymphopenia were evaluated. After 8 weeks of age, when obese diabetes progresses, T lymphopenia in both spleen and thymus developed and all T-lymphocyte subsets examined were similarly reduced compared to lean (-/X) littermates, indicating non-selective T lymphopenia in db/db mice. Thymectomy performed at 5 wk of age, when neither T lymphopenia nor NIDDM yet presents, had no significant effect on the development of T lymphopenia. Furthermore, pair feeding until 30 weeks of age produced normal body weight and normoglycemia with still marked hyperinsulinemia, but failed to correct T lymphopenia in db/db mice. In conclusion, our results suggest that T lymphopenia may develop non-selectively and independently of either thymic dysfunction or obese diabetes in db/db mice.
Kimura
M
M
The Third Department of Internal Medicine, Yokohama City University School of Medicine, Kanazawa, Yokohama, Japan.
Tanaka
S
S
Isoda
F
F
Sekigawa
K
K
Yamakawa
T
T
Sekihara
H
H
D000818:Animals; D003920:Diabetes Mellitus / Q000276:immunology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000276:immunology*; D004032:Diet; D004195:Disease Models, Animal; D018450:Disease Progression; D005434:Flow Cytometry; D008231:Lymphopenia / Q000150:complications*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009765:Obesity; D013154:Spleen / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013934:Thymectomy; D013950:Thymus Gland / Q000276:immunology*; D015431:Weight Loss / Q000276:immunology