Transdermal delivery of Syzygium aromaticum-derived oleanolic acid by dermal patches in streptozotocin-induced diabetic rats: effects on some selected metabolic parameters

Background and Objective. Glucose transport via GLUT1 protein could be one of additional mechanisms of the antidiabetic action of sulfonylureas. Here, the GLUT1 gene and the protein expression was studied in rats in the course of severe and mild streptozotocin-induced diabetes mellitus and under glibenclamide treatment. Material and Methods. Severe and mild diabetes mellitus was induced using different streptozotocin doses and standard or high fat chow. Rats were treated with glibenclamide (2 mg/kg daily, per os for 6 weeks). The therapeutic effect of glibenclamide was monitored by measuring several metabolic parameters. The GLUT1 mRNA and the protein expression in the kidneys, heart, and liver was studied by means of real-time R T-PCR and immunohistochemistry. Results. The glibenclamide treatment decreased the blood glucose concentration and increased the insulin level in both models of severe and mild diabetes mellitus. Severe diabetes mellitus provoked an increase in both GLUT1 gene and protein expression in the kidneys and the heart, which was nearly normalized by glibenclamide. In the kidneys of mildly diabetic rats, an increase in the GLUT1 gene expression was neither confirmed on the protein level nor influenced by the glibenclamide treatment. In the liver of severely diabetic rats, the heart and the liver of mildly diabetic rats, the GLUT1 gene and the protein expression was changed independently of each other, which might be explained by abortive transcription, and pre- and posttranslational modifications of gene expression. Conclusions. The GLUT1 expression was found to be affected by the glucose and insulin levels and can be modulated by glibenclamide in severely and mildly diabetic rats. Glibenclamide can prevent the liver damage caused by severe hyperglycemia.

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The Haematological Effects of Oleanolic Acid in Streptozotocin-Induced Diabetic Rats: Effects on Selected Markers

Journal of Diabetes Research ◽

10.1155/2019/6753541 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Charity M. Baloyi ◽

A. Khathi ◽

Ntethelelo H. Sibiya ◽

Phikelelani S. Ngubane

Keyword(s):

Oxidative Stress ◽

Oleanolic Acid ◽

Blood Glucose Concentration ◽

Glycated Haemoglobin ◽

Diabetic Control ◽

Cardiovascular Complications ◽

Diabetic Rats ◽

Control Group ◽

Rbc Indices ◽

Notable Increase

Background. Sustained hyperglycaemia leads to the development of haematological alterations which, if left untreated, is associated with cardiovascular complications. Insulin is the mainstay drug in type 1 diabetes mellitus (T1D); however, the use of insulin is associated with haematological alterations that could further worsen cardiovascular complications. Therefore, the aim of the study was to investigate the haematological effects of oleanolic acid (OA) in streptozotocin- (STZ-) induced diabetic rats. Methods. The animals were separated into five groups; the nondiabetic group (ND), the diabetic control group (DC), and the treatment groups of insulin (170 μg/kg, s.c), metformin (500 mg/kg, p.o), and OA (80 mg/kg, p.o). OA was administered orally twice a day. Thereafter, the animals were sacrificed, and blood and tissues were collected for haematological, hormonal, and oxidative status analysis. Results. Untreated diabetic rats exhibited hyperglycaemia, elevated glycated haemoglobin (HbA1c), oxidative stress, and a reduced erythropoietin (EPO) concentration when compared to ND rats. However, administration of OA attenuated hyperglycaemia, HbA1c, and EPO concentrations compared to DC rats. The reduction of blood glucose concentration, HbA1c, and improved EPO concentrations was further associated with a notable increase in red blood cell (RBC) count and other RBC indices. We also observed an increase in the antioxidant status of the RBCs with a concomitant decrease in oxidative stress. Conclusion. These findings suggest that OA improves diabetes-induced haematological changes caused by hyperglycaemia and attenuates the progression of cardiovascular complications in DM individuals.

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Plant-derived oleanolic acid ameliorates markers of subclinical inflammation and innate immunity activation in diet-induced pre-diabetic rats

Therapeutic Advances in Endocrinology and Metabolism ◽

10.1177/2042018820935771 ◽

2020 ◽

Vol 11 ◽

pp. 204201882093577

Author(s):

Mlindeli Gamede ◽

Lindokuhle Mabuza ◽

Phikelelani Ngubane ◽

Andile Khathi

Keyword(s):

Cell Count ◽

Oleanolic Acid ◽

Proinflammatory Cytokines ◽

Immune Activation ◽

Molecular Mechanisms ◽

Dietary Intervention ◽

Immune Cell ◽

Diabetic Rats ◽

Sprague Dawley ◽

Cell Counts

Aims: Sub-clinical inflammation during pre-diabetes is one of the predisposing factors that facilitates the progression of pre-diabetes to type 2 diabetes. The administration of oleanolic acid (OA) with or without dietary intervention ameliorates the metabolic and cardiovascular complications in diet-induced pre-diabetes animal models of pre-diabetes. This study aimed to investigate whether OA can also suppress immune activation and ameliorate pro-inflammatory markers. Methods: Pre-diabetes was induced by feeding Sprague Dawley rats a high-fat high carbohydrate diet for 20 weeks. The pre-diabetic rats were then treated with OA (80 mg/kg) or metformin (500 mg/kg) in the presence or absence of dietary interventions for a period of 12 weeks. At the end of the treatment period, the animals were euthanised and whole blood was used for platelet and immune cell count while plasma was used for fibrinogen, cluster differentiation 40 ligand and pro-inflammatory cytokine evaluation. Results: The results of this study revealed that OA, with or without dietary intervention, improved lipid metabolism by restoring high-density lipoprotein (HDL) and low-density lipoproteins (LDLs) as well as reducing platelets and immune cell counts. Furthermore, OA also decreased plasma proinflammatory cytokines, including tumour necrosis factor-α and -1β. Markers of immune activation such as C-reactive protein, fibrinogen, and CD40L were also decreased upon administration of OA with or without dietary intervention. Conclusion: The findings of this study suggest that OA may provide an alternative to prevent the progression of pre-diabetes to overt diabetes. This was evident by the reduction of differential white blood cell count and proinflammatory cytokines that exercebate insulin resistance. However, more studies are needed to elucidate the molecular mechanisms and to improve efficacy.

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