A Simplified Streptozotocin-Induced Diabetes Model in Nude Mice

Abstract

Preclinical studies of human cellular and tissue-based products (HCT/Ps) for transplantation therapy of type 1 diabetes mellitus (T1DM) necessarily involve animal models, particularly mouse models of diabetes induced by streptozotocin (STZ). These models should mimic the clinical and metabolic manifestations of T1DM in humans (face validity) and be similar to T1DM in terms of the pathogenetic mechanism (construct validity). Furthermore, since HCT/Ps contain human cells, modeling of diabetes in immune-deficient animals is obligatory. Here we describe the most simplified diabetes model in Nude mice. Diabetes was induced in 31 males by a single intraperitoneal injection of STZ in normal saline at a medium-to-high dose of 150 mg/kg body weight. Fourteen control animals received only saline. Non-fasting plasma glucose (PG) levels were measured periodically for 50 days. All STZ-treated mice survived beyond 50 days. By day 15 after STZ administration, 22 of 31 (71%) mice developed stable diabetes based on the following criteria: (1) non-fasting PG ≥ 15 mmol/L on consecutive measurements up until day 50; (2) no diabetes remission. The mean non-fasting PG in mice with stable diabetes over the period of 35 days was equal to 25.7 mmol/L. On day 50, mean plasma insulin concentration, mean pancreatic insulin content, and the average number of β-cells in pancreatic islets were 2.6, 8.4, and 50 times lower, respectively, than in the control animals. We consider that our Nude mouse model of diabetes meets face validity and construct validity criteria and can be used in preclinical studies of HCT/Ps.

Keywords: Nude mice; animal model; diabetes mellitus; streptozotocin.

Fig. 1

Diabetes incidence in group D (Kaplan–Meyer analysis). The arrow indicates STZ injection; the asterisk marks the onset of diabetes remission in one of the animals

Fig. 2

Non-fasting PG values in group D mice with stable diabetes and group C mice during the observation period. The arrow indicates STZ injection

Fig. 3

Body weight of group D mice with stable diabetes and group C mice at the beginning and at the end of the observation period

Fig. 4

Changes in PG and plasma insulin content during IPGTT in group D mice with stable diabetes and group C mice

Fig. 5

Insulin content in the pancreatic tissue of group D mice with stable diabetes and group C mice on observation day 50

Fig. 6

Pancreatic islets in group D mice with stable diabetes and group C mice on day 50. Light microscopy, immunohistochemical staining for insulin, 400× magnification. Scale bar, 100 μm

Fig. 7

Pancreatic islets in group D mice with stable diabetes and group C mice on day 50. Fluorescent microscopy; β-cells were stained for insulin (green); nuclei were stained with DAPI (magenta); 200× magnification. Scale bar, 100 μm