Construction and evaluation of STZ-induced diabetes and diabetic kidney disease models in C57BL/6J mice

Abstract

Objective: To explore the optimal strategy for streptozotocin (STZ)-induced models of diabetes mellitus (DM) and Diabetic kidney disease (DKD) in C57BL/6J mice, and to analyze potential factors influencing model stability.

Methods: Forty-five 6-week-old male C57BL/6J mice were randomly assigned to six groups: normal control (CON), unilateral nephrectomy control (CU), standard diet with STZ (CS), standard diet with unilateral nephrectomy and STZ (CUS), high-fat diet with STZ (HS), and high-fat diet with unilateral nephrectomy and STZ (HUS). Mice in the HS and HUS groups received a high-fat diet (HFD) for 6 weeks, followed by unilateral nephrectomy (UN) or sham surgery, and were then administered STZ (35 or 45 mg/kg/day, intraperitoneally) for five consecutive days to induce DM. DM induction was confirmed when two consecutive random blood glucose (RBG) measurements were ≥ereu mmol/L. Throughout the study, RBG, body weight, and urine albumin-to-creatinine ratio (UACR) were monitored longitudinally. At 19 weeks post-induction, mice were euthanized for kidney weight assessment and histopathological examination.

Result: All STZ-treated mice initially developed diabetes (100%); however, sustained hyperglycemia was not achieved in all cases. Glycemic stability was strongly influenced by the induction strategy (P<0.05). Specifically, 45 mg/kg/day STZ with a normal diet yielded only a 14.3% remission rate (2/14), whereas 35 mg/kg/day STZ with a HFD resulted in a 62.5% remission rate (10/16). Although 45 mg/kg/day STZ combined with a HFD maintained persistent hyperglycemia, it was accompanied by excessive mortality (80%, 8/10). UN was not associated with glycemic stability (P > 0.05); however, it markedly accelerated DKD progression and exhibited a synergistic effect with HFD. Furthermore, compared with mice exhibiting partial glycemic remission, those with stable hyperglycemia demonstrated significantly higher kidney weight, kidney-to-body weight ratio, and UACR (P<0.05).

Conclusion: An appropriate dose of STZ in combination with UN and HFD represents an optimal strategy for establishing an STZ-induced DKD model in C57BL/6J mice, effectively recapitulating the clinical and pathological features of human DKD and providing a robust platform for mechanistic research and therapeutic development.

Keywords: C57BL/6J mice; diabetes mellitus; diabetic nephropathies; models animal; streptozotocin.

Figure 1

Workflow for establishing the diabetic mouse model. The day of successful diabetes induction was designated as week 0 (0W). HFD, high-fat diet; STZ, streptozotocin; UACR, urine albumin-to-creatinine ratio.

Figure 2

Left nephrectomy procedure in mice.

Figure 3

RBG dynamics in each experimental group. CON, normal control; CU, unilateral nephrectomy control; CS, STZ-induced diabetic mice on standard diet; CUS, STZ + unilateral nephrectomy on standard diet; HS, STZ-induced diabetic mice on high-fat diet; HUS, STZ + unilateral nephrectomy on high-fat diet. Throughout the modeling period, mice with RBG ≥ 16.7 mmol/L were considered diabetic.

Figure 4

Temporal changes in body weight across experimental groups.

Figure 5

Kidney weight, kidney-to-body weight ratio, and UACR in each group of mice. (A) Comparison of kidney weight among the six groups (CON, CU, CS, CUS, HS, HUS). (B) Comparison of kidney-to-body weight ratio among the six groups. (C) UACR changes before sacrifice in each group. (D) UACR comparison among groups after excluding mice with recovered blood glucose. The HS group had only one remaining mouse due to glycemic recovery; therefore, this group was not included in the statistical analysis. (A–C) Sample sizes: CON (n=5), CU (n=4), CS (n=4), CUS (n=3), HS (n=8), HUS (n=13). (D) Sample sizes: CON (n=5), CU (n=4), CS (n=3), CUS (n=3), HS (n=1), HUS (n=8). Data are presented as mean ± SD. *P < 0.05, ***P < 0.001.

Figure 6

Histopathological analysis of mouse kidneys in each group. Kidney tissues were collected at 19 weeks post-modeling and examined by electron microscopy. Sections were stained with hematoxylin and eosin (HE) and periodic acid–Schiff (PAS). TEM: Transmission Electron Microscope.

Figure 7

Comparison of random blood glucose (RBG), body weight, and UACR among DM, NDM, and control mice. CON, normal control; CU, unilateral nephrectomy control; DM, diabetic mice with persistent hyperglycemia; NDM, diabetic mice with spontaneous blood glucose recovery. (A–E) Sample sizes: CON (n=5), CU (n=4), NDM (n=13), DM (n=15). Data are presented as mean ± SD. *P < 0.05, **P < 0.01, ***P < 0.001.