Type 2 diabetes phenotypes in male and female C57BL/6J mice with the leptin receptor mutation (B6-db; B6.BKS(D)-Leprdb/J) include:
- Severe obesity (Figure 1 and Table 2)
- Transient hyperglycemia (Figure 2 and Table 1). B6-db/db glucose levels peak then decrease with time due to pancreatic islet cell hypertrophy. By contrast, BKS-db/db mice sustain high blood glucose throughout life.
- Elevated serum total cholesterol, HDL cholesterol, triglycerides and glucose at 8 weeks of age; elevated serum total cholesterol, HDL cholesterol and glucose at 16 weeks of age (Table 3)
- Glucose intolerance at 8 & 16 weeks (Figure 3)
Complete results, including spleen flow cytometry data, are available from the Mouse Phenome Database.
Figure 1 Body weight growth curve. Cohorts contained approximately 80 db/db and 40 db/+ mice per sex. Mice were fed a diet containing 6% fat (LabDiet® 5K52 formulation).
Figure 2 Non-fasted glucose. Blood glucose levels of male and female mice between the ages of 4 and 16 weeks. Submandibular blood glucose measurements were obtained using a OneTouch Ultra 2 or UltraMini hand-held glucometer that was validated with a control glucose solution on each day of use. Values represent the mean and one standard deviation.
Figure 3 Glucose tolerance tests. Blood glucose levels during glucose tolerance tests (GTT) at 8 and 16 weeks of age. Following a 16 hour fast, an initial submandibular blood glucose reading was taken and mice were administered glucose by IP injection at 2g/kg body weight. Blood glucose was measured in 30 minute intervals. Any result exceeding the maximum reading of the meter was recorded as 600 mg/dL. Each data point represents the mean and one standard deviation of 10-20 mice.
Table 1 Distribution of homozygous (db/db) blood glucose values. The blood glucose values shown in Figure 2 were grouped into ranges to show the reversion to non-diabetic values as db/db mice age. Rows indicate the percentage of mice in the indicated ranges, with the exception of the final row that states the number of mice analyzed.
Glucose Range (mg/dL) | 4 Weeks |
6 Weeks |
8 Weeks |
10 Weeks |
12 Weeks |
14 Weeks |
16 Weeks |
18 Weeks |
20 Weeks |
|||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Males | Females | Males | Females | Males | Females | Males | Females | Males | Females | Males | Females | Males | Females | Males | Females | Males | Females | |
< 250 | 59% | 58% | 39% | 43% | 21% | 37% | 41% | 34% | 33% | 57% | 48% | 63% | 54% | 59% | 84% | 74% | 74% | 91% |
250 - 349 | 24% | 30% | 49% | 40% | 51% | 39% | 25% | 40% | 37% | 25% | 25% | 26% | 30% | 29% | 5% | 17% | 21% | 0% |
350 - 450 | 11% | 13% | 6% | 13% | 18% | 18% | 22% | 13% | 19% | 9% | 16% | 3% | 9% | 4% | 5% | 4% | 0% | 4% |
> 450 | 6% | 0% | 6% | 5% | 10% | 7% | 13% | 13% | 11% | 9% | 11% | 8% | 7% | 9% | 5% | 4% | 5% | 4% |
# Mice | 80 | 80 | 80 | 80 | 80 | 90 | 79 | 77 | 79 | 76 | 56 | 76 | 56 | 56 | 19 | 23 | 19 | 23 |
Table 2 Body Composition. Mice were weighed and then analyzed using a Lunar PIXImus DEXA scanner. Calculations of body composition exclude the head. Values represent mean and one standard deviation of 10 non-fasted mice per age, sex and genotype. Results were analyzed separately by age and sex using two-way ANOVA with Sidak’s multiple comparisons test to identify values that differed significantly between genotypes, using GraphPad Prism version 6.07 for Windows (GraphPad Software).
Age & Sex | Genotype | Body Weight (g) | Bone Mineral Density (g/cm2) | Bone Mineral Content (g) | Bone Area (cm2) | Lean Tissue (g) | Fat Tissue (g) | Percent Fat Tissue |
---|---|---|---|---|---|---|---|---|
8 Week Males | db/db | 40.4 ± 3.2a | 0.047 ± 0.002 | 0.44 ± 0.07 | 9.4 ± 1.2 | 17.3 ± 2.0a | 21.7 ± 2.4a | 55.6 ± 4.0a |
db/+ | 28.8 ± 1.5a | 0.053 ± 0.002 | 0.46 ± 0.03 | 8.8 ± 0.5 | 21.2 ± 1.3a | 6.2 ± 0.8a | 22.5 ± 2.3a | |
8 Week Females | db/db | 36.0 ± 2.6a | 0.044 ± 0.001 | 0.34 ± 0.03 | 7.7 ± 0.6 | 15.5 ± 1.1 | 19.9 ± 1.6a | 56.1 ± 1.9a |
db/+ | 23.0 ± 1.2a | 0.050 ± 0.002 | 0.39 ± 0.03 | 7.8 ± 0.8 | 15.5 ± 0.9 | 6.5 ± 0.8a | 29.6 ± 2.8a | |
16 Week Males | db/db | 54.4 ± 3.1a | 0.050 ± 0.001 | 0.53 ± 0.05 | 10.6 ± 1.0 | 20.2 ± 1.7b | 32.5 ± 3.2a | 61.7 ± 3.3a |
db/+ | 34.1 ± 2.9a | 0.060 ± 0.003 | 0.58 ± 0.03 | 9.6 ± 0.5 | 23.9 ± 1.4b | 9.4 ± 2.0a | 27.9 ± 3.9a | |
16 Week Females | db/db | 55.3 ± 2.7a | 0.050 ± 0.002 | 0.49 ± 0.08 | 9.8 ± 1.4 | 19.3 ± 1.1 | 33.9 ± 3.0a | 63.7 ± 2.0a |
db/+ | 29.1 ± 2.1a | 0.058 ± 0.001 | 0.50 ± 0.04 | 8.6 ± 0.6 | 17.8 ± 0.9 | 10.8 ± 1.8a | 37.5 ± 3.9a | |
a P ≤ 0.0001 b P ≤ 0.001 |
Table 3 Clinical chemistry. All values were measured from serum collected from submandibular blood except HbA1c, which was measured from submandibular whole blood. Values represent mean and one standard deviation of 10-20 non-fasted mice per age and diet group. Results were obtained using a Beckman Coulter AU680 chemistry analyzer. Results were analyzed separately by age and sex using two-way ANOVA with Sidak’s multiple comparisons test to identify values that differed significantly by genotype, using GraphPad Prism version 6.07 for Windows (GraphPad Software).
Age & Sex | Genotype | Total Cholesterol (mg/dL) | HDL Cholesterol (mg/dL) | LDL Cholesterol (mg/dL) | Triglycerides (mg/dL) | Free Fatty Acids (mEq/L) | Glucose (mg/DL) | HbA1c (NGSP %) |
---|---|---|---|---|---|---|---|---|
8 Week Males | db/db | 218 ± 62a | 139 ± 41b | 8.7 ± 2.1 | 200 ± 66b | 1.2 ± 0.4 | 399 ± 122a | 7.8 ± 0.8 |
db/+ | 125 ± 18a | 92 ± 14b | 4.4 ± 1.4 | 150 ± 38b | 1.2 ± 0.4 | 207 ± 41a | 5.7 ± 0.3 | |
8 Week Females | db/db | 216 ± 33a | 137 ± 19a | 8.3 ± 1.4 | 203 ± 48a | 1.3 ± 0.4 | 310 ± 108a | 7.4 ± 0.8 |
db/+ | 109 ± 10a | 82 ± 9a | 5.5 ± 1.3 | 138 ± 32a | 1.3 ± 0.3 | 192 ± 22a | 5.4 ± 0.4 | |
16 Week Males | db/db | 291 ± 75a | 174 ± 27a | 20.0 ± 12.4 | 131 ± 27 | 1.4 ± 0.4 | 273 ± 82a | 10.7 ± 1.7 |
db/+ | 123 ± 36a | 95 ± 26a | 3.3 ± 1.3 | 139 ± 34 | 1.5 ± 0.4 | 184 ± 49a | 6.2 ± 0.7 | |
16 Week Females | db/db | 282 ± 92a | 166 ± 39b | 18.3 ± 8.4 | 167 ± 80 | 2.0 ± 0.9 | 370 ± 197a | 8.5 ± 1.9 |
db/+ | 110 ± 15a | 86 ± 9b | 6.5 ± 1.9 | 113 ± 26 | 1.6 ± 0.3 | 183 ± 39a | 6.2 ± 0.7 | |
a P ≤ 0.0001 b P ≤ 0.01 |