Lab Anim Res.  2015 Mar;31(1):1-6. 10.5625/lar.2015.31.1.1.

An age-dependent alteration of the respiratory exchange ratio in the db/db mouse

• Choi HM
• Kim HR
• Kim EK
• Byun YS
• Won YS
• Yoon WK
• Kim HC
• Kang JG
• Nam KH

• KMID: 1787645
• DOI: http://doi.org/10.5625/lar.2015.31.1.1

Abstract

The leptin receptor-deficient db/db mouse is a rodent model of type 2 diabetes and obesity. Diabetes in db/db mice shows an age-dependent progression, with early insulin resistance followed by an insulin secretory defect resulting in profound hyperglycemia. However, there is insufficient data on agedependent changes of energy metabolism in db/db mice. We demonstrated an age-dependent decrease in the respiratory exchange ratio (RER), calculated by a ratio of VO2/VCO2, in db/db mice. The RER determined by indirect calorimetry, was 1.03 in db/db mice under 6 weeks of age, which were similar to those in heterozygote (db/+) and wild-type (+/+) mice. However, RER decreased from approximately 0.9 to 0.8 by 10 weeks of age and subsequently returned to approximately 0.9 at 22 weeks of age. The changes in RER were concurrent with the alterations in body weight and blood glucose level. However, other metabolic indicators such as glucose tolerance, changes in body fat mass, and urinary glucose levels, did not change with age. The results suggested that the energy source utilized in db/db mice changed with the age-related progression of diabetes.

Keyword

Respiratory exchange ratio; age-dependency; indirect calorimetry; db/db mouse

MeSH Terms

Adipose Tissue
Animals
Blood Glucose
Body Weight
Calorimetry, Indirect
Energy Metabolism
Glucose
Heterozygote
Hyperglycemia
Insulin
Insulin Resistance
Leptin
Mice*
Obesity
Rodentia
Blood Glucose
Glucose
Insulin
Leptin

Figure

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  Figure 1 Experimental design. Three mouse groups with genotypes of homozygotes (db/db), heterozygotes (db/+) and wild (+/+) type were housed under specific pathogen free conditions (n=5 for each group). The mice were subjected to various experiments at the indicated age. Lined arrow; indirect calorimetry, dotted arrow; urine analysis, intraperitoneal glucose tolerance test and measurement of blood glucose level, arrow heads; body fat measurement.

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  Figure 2 Body weight change and water consumption. Three mouse groups with genotypes of homozygotes (db/db), heterozygotes (db/+) and wild (+/+) type were housed under specific pathogen free conditions (n=5 for each group). The body weight changes (A) and water consumptions (B) in the mouse groups were determined from 5- to 30-weeks of age. ⋆ means significant difference (P<0.05). Data are presented as mean±SD. •; db/db mice, ▴; db/+ mice, ▫; +/+ mice.

• 

  Figure 3 The changes of respiratory exchange ratio (RER) and related parameters in db/db mice. Indirect calorimetry were performed with 3 mouse groups of homozygotes (db/db), heterozygotes (db/+) and wild (+/+) type (n=5 for each group). Mice were tested in individual clear chambers with a stainless steel elevated wire floor. Each chamber contained a sipper tube delivering water, a food tray connected to a balance and photobeams to detect activities. The RER (A) and heat production were calculated using carbon dioxide produced and oxygen consumed and the activity (C) was expressed as the number of beams cut during the measurement period. •; db/db mice, ▴; db/+ mice, ▫; +/+ mice, ⋆ means significant difference (P<0.05). Data are presented as mean±SD.

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  Figure 4 The blood glucose change and glucose tolerance in db/db mice. Fasting blood glucose levels were determined for the homozygote (db/db), heterozygote (db/+) and wild-type (+/+) mice from 4 to 31 weeks of age (n=5 for each group). To determine the glucose tolerance ability, after abdominal challenge of 2 g of glucose/kg body weight, the blood glucose levels were determined at 15, 30, 60 and 120 min. The IPGTT results measured at 4 weeks of age were shown (B). •; db/db mice, ▴; db/+ mice, ▫; +/+ mice, ⋆ means significant difference (P<0.05). Data are presented as means±SD. Note that 600 mg/dL of glucose is the detection limit for the glucometer used in this study.

Reference

1. Shaw JE, Sicree RA, Zimmet PZ. Global estimates of the prevalence of diabetes for 2010 and 2030. Diabetes Res Clin Pract. 2010; 87(1):4–14. PMID: 19896746.

2. Guariguata L, Whiting DR, Hambleton I, Beagley J, Linnenkamp U, Shaw JE. Global estimates of diabetes prevalence for 2013 and projections for 2035. Diabetes Res Clin Pract. 2014; 103(2):137–149. PMID: 24630390.

3. King AJ. The use of animal models in diabetes research. Br J Pharmacol. 2012; 166(3):877–894. PMID: 22352879.

4. Cohran VC, Bates MD. Leptin signaling and obesity: weight and see. Gastroenterology. 2003; 124(5):1546–1548. PMID: 15534982.

5. Lewis GF, Carpentier A, Adeli K, Giacca A. Disordered fat storage and mobilization in the pathogenesis of insulin resistance and type 2 diabetes. Endocr Rev. 2002; 23(2):201–229. PMID: 11943743.

6. Hummel KP, Dickie MM, Coleman DL. Diabetes, a new mutation in the mouse. Science. 1966; 153(3740):1127–1128. PMID: 5918576.

7. Ahima RS, Prabakaran D, Mantzoros C, Qu D, Lowell B, Maratos-Flier E, Flier JS. Role of leptin in the neuroendocrine response to fasting. Nature. 1996; 382(6588):250–252. PMID: 8717038.

8. Chen H, Charlat O, Tartaglia LA, Woolf EA, Weng X, Ellis SJ, Lakey ND, Culpepper J, Moore KJ, Breitbart RE, Duyk GM, Tepper RI, Morgenstern JP. Evidence that the diabetes gene encodes the leptin receptor: identification of a mutation in the leptin receptor gene in db/db mice. Cell. 1996; 84(3):491–495. PMID: 8608603.

9. Zhang Y, Proenca R, Maffei M, Barone M, Leopold L, Friedman JM. Positional cloning of the mouse obese gene and its human homologue. Nature. 1994; 372(6505):425–432. PMID: 7984236.

10. Pelleymounter MA, Cullen MJ, Baker MB, Hecht R, Winters D, Boone T, Collins F. Effects of the obese gene product on body weight regulation in ob/ob mice. Science. 1995; 269(5223):540–543. PMID: 7624776.

11. Heiman ML, Ahima RS, Craft LS, Schoner B, Stephens TW, Flier JS. Leptin inhibition of the hypothalamic-pituitary-adrenal axis in response to stress. Endocrinology. 1997; 138(9):3859–3863. PMID: 9275075.

12. Brandi LS, Bertolini R, Calafa M. Indirect calorimetry in critically ill patients: clinical applications and practical advice. Nutrition. 1997; 13(4):349–358. PMID: 9178287.

13. Battezzati A, Viganò R. Indirect calorimetry and nutritional problems in clinical practice. Acta Diabetol. 2001; 38(1):1–5. PMID: 11487171.

14. Schwenk A, Meriläinen PT, Macallan DC. Indirect calorimetry in patients with active respiratory infection--prevention of cross-infection. Clin Nutr. 2002; 21(5):385–388. PMID: 12381335.

15. GLK . Measurements in physical therapy by Jules M. Rothstein Clinics in Physical Therapy Vol. 7. Churchill Livingstone, 1985. £27.50. Clin Biomech (Bristol, Avon). 1987; 2(1):61.

16. Osborn O, Sanchez-Alavez M, Brownell SE, Ross B, Klaus J, Dubins J, Beutler B, Conti B, Bartfai T. Metabolic characterization of a mouse deficient in all known leptin receptor isoforms. Cell Mol Neurobiol. 2010; 30(1):23–33. PMID: 19582570.

17. Li YY, Yu LF, Zhang LN, Qiu BY, Su MB, Wu F, Chen DK, Pang T, Gu M, Zhang W, Ma WP, Jiang HW, Li JY, Nan FJ, Li J. Novel small-molecule AMPK activator orally exerts beneficial effects on diabetic db/db mice. Toxicol Appl Pharmacol. 2013; 273(2):325–334. PMID: 24055643.

18. Muoio DM, Lynis Dohm G. Peripheral metabolic actions of leptin. Best Pract Res Clin Endocrinol Metab. 2002; 16(4):653–666. PMID: 12468413.

19. Harris RB, Mitchell TD, Yan X, Simpson JS, Redmann SM Jr. Metabolic responses to leptin in obese db/db mice are strain dependent. Am J Physiol Regul Integr Comp Physiol. 2001; 281(1):R115–R132. PMID: 11404285.

20. Trayhurn P, James WP. Thermoregulation and non-shivering thermogenesis in the genetically obese (ob/ob) mouse. Pflugers Arch. 1978; 373(2):189–193. PMID: 565045.

21. Lee SM, Bressler R. Prevention of diabetic nephropathy by diet control in the db/db mouse. Diabetes. 1981; 30(2):106–111. PMID: 7009265.

22. Edgel KA, McMillen TS, Wei H, Pamir N, Houston BA, Caldwell MT, Mai PO, Oram JF, Tang C, Leboeuf RC. Obesity and weight loss result in increased adipose tissue ABCG1 expression in db/db mice. Biochim Biophys Acta. 2012; 1821(3):425–434. PMID: 22179025.

23. Dittrich HM, Hahn von Dorsche H. [The anatomical and histological investigation of the pancreas in the 19th century and till the discovery of insulin (1921). 2. The pancreas research from the discovery of islets (1869) till the discovery of pancreasdiabetes (1889) (author's transl)]. Anat Anz. 1978; 143(3):231–241. PMID: 686388.