Pharmacological induction of diabetes mellitus in pregnant female mice: a comparison of two doses and routes of administration

OBJECTIVE: This study aimed to compare two routes of administration and different dosages of streptozotocin (STZ) for the pharmacological induction of gestational diabetes mellitus (GDM) in pregnant CD1 females. MATERIALS AND METHODS: 35 female CD1 mice were divided into 5 groups (n = 7). Diabetes mellitus (DM) was induced with STZ by two routes and two doses: 1) Control Group without administration of STZ (CL), 2) Intraperitoneal Group with 200 mg of STZ/Kg of weight (IP200), 3) Intraperitoneal Group with 230 mg of STZ/Kg of weight (IP230), 4) Subcutaneous Group with 200 mg of STZ/Kg of weight (SC200) and 5) Subcutaneous Group with 230 mg of STZ/Kg of weight (SC230). Body weight, food and water intake, glycemia, Homeostatic Model Assessment of Insulin Resistance Index (HOMA-IR), survival, and birth rate were identified. RESULTS: The SC230 group turned out to be the most effective dose and route for the induction of GDM in pregnant females. This scheme managed to reproduce sustained hyperglycemia with high HOMA-IR, the presence of polyphagia, polydipsia, and weight loss. In addition, the birth rate and survival were high compared to the other doses and routes of administration. CONCLUSIONS: The administration of a single dose of 230 mg/kg of weight by subcutaneous route supposes advantages compared to previously used models since it decreases the physiological stress due to manipulation and the costs since it does not require repeated doses or adjuvants such as high lipid diets to potentiate the diabetogenic effect of STZ.

Graphical Abstract

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Chronic Consumption of Sweeteners and Its Effect on Glycaemia, Cytokines, Hormones, and Lymphocytes of GALT in CD1 Mice

BACKGROUND

The consumption of sweeteners has increased in recent years, being used to control body weight and blood glucose. However, they can cause increased appetite, modification of immune function, and secretion of hormones in the GALT.

OBJECTIVE

To assess the effect of chronic sweetener consumption on glycaemia, cytokines, hormones, and GALT lymphocytes in CD1 mice.

MATERIAL AND METHODS

72 CD1 mice divided into 3 groups were used: (a) baseline, (b) middle, and (c) final. Groups (b) and (c) were divided into 4 subgroups: (i) Control, (ii) Sucrose, (iii) Sucralose, and (iv) Stevia. The following were determined: body weight, hormones (GIP, insulin, and leptin), lymphocytes CD3+T cells and CD19+B cells, IgA+ plasma cells, and cytokines (IL-4, IL-5, IFN-γ, and TNF-α).

RESULTS

Sucralose reduces secretion of GIP and glycaemia but does not modify insulin concentration, increases body weight, and reduces food intake. Stevia increases the secretion of GIP, insulin, leptin, body weight, and glycaemia but keeps food consumption normal. Sucralose and Stevia showed a higher percentage of CD3+T cells, CD19+B cells, and IgA+ plasma cells in Peyer's patches, but only Stevia in lamina propria.

CONCLUSION

Sweeteners modulate the hormonal response of cytokines and the proliferation of lymphocytes in the intestinal mucosa.

Vitamins and type 2 diabetes mellitus

The present review evaluates the relationship between type 2 diabetes mellitus and individual or combined vitamins. Antioxidant vitamins A, C and E are found decreased in diabetic subjects, possibly due to an increased need to control the excessive oxidative stress produced by abnormalities in glucose metabolism. On the other hand, retinol binding protein exerts a modulating effect, as it has adipokine functions. With respect to the B group vitamins, thiamin, pyridoxine and biotin have been found decreased but the mechanisms are not clear, however supplementation has shown some improvement of the metabolic control in diabetic patients. The absorption of folic acid and vitamin B12 is importantly decreased by the prolongued use of metformin, which is the first choice drug in uncomplicated diabetes, thus these two nutrients have been found deficient in the disease and most probably need to be supplemented regularly. On the other hand, vitamin D is considered a risk factor for the development of diabetes as well as its complications, particularly cardiovascular ones. Although some studies have found an association of vitamin K intake with glucose metabolism further research is needed. Studies on the use of multivitamin supplements have shown unconclusive results. After reviewing the evidence, no real recommendation on the use of vitamin supplements in type 2 diabetes mellitus can be issued, however patients using metformin during prolongued periods may need folic acid and vitamin B12.

Repeated restraint stress reduces the number of IgA-producing cells in Peyer's patches

The few reports that have analyzed the effects of stress on the immune cells of the intestinal mucosa or the functions of these cells have tended to focus on S-IgA levels in saliva, and these studies have shown contradictory results. The principal objective of this study was to analyze the effects of repeated restraint stress on the number and distribution of immune cells in Peyer's patches (PPs) as well as the effects of glucocorticoid and catecholamine administration on the same stress-related parameters. Upon analyzing the effect of repeated restraint stress on PPs, it was found that there was no modification in the morphological structure of the PPs but that restraint stress reduced the total number of lymphocytes and the number of CD8+ T cells, B cells, and plasma cells in PPs. Only at the site of PPs where IgA-producing plasma cells are most numerous (the dome) was a decrease found in this type of cell. These effects were due at least in part to the effect of glucocorticoids and catecholamines. Since IgA produced in PPs is a natural antibody that impedes bacterial infections, repeated stress may favor the entry of pathogens through the intestine.