The comparative effects of metformin and insulin on the kidney, lung and heart of streptozotocin-induced diabetic female Wistar rats

Abstract

Background: Diabetes mellitus is a metabolic disorder resulting in chronic hyperglycaemia. It is associated with long-term complications such as damage or dysfunction of organs, especially the eyes, kidneys, nerves, heart, and blood vessels. Despite significant achievements in treatment modalities and preventive measures, the prevalence of diabetes keeps rising.

Objectives: The study assessed the effects of metformin and insulin in glycaemic control and on the kidney, lungs and heart of streptozotocin-induced diabetic female Wistar rats.

Methods: Twenty Wistar rats weighing 100-160g were randomly divided into four groups of 5 animals each. Group1 was the non diabetic control group while diabetes was induced in groups 2-4 using streptozotocin. Group 2 was given water only, while groups 3 and 4 were treated with insulin (1 IU daily) and metformin (200 mg/kg) for 3 weeks respectively. Blood glucose and major organs (kidney, lung and heart) were studied.

Results: Metformin and insulin produced statistically significant decreases in blood glucose levels of 40.7% and 33.1% respectively. Kidney histology showed normal glomeruli in all treated group, while mild haemorrhage was seen in diabetic group and tubular necrosis in the metformin group. Lung histology showed reduction in alveolar space and mild to moderate chronic inflammatory cells in tests groups, there was sparing of peripheral lung tissue in metformin group. The heart histology showed both diabetic and insulin groups having pericardial congestion and moderate myocardial fatty change, while the metformin-treated group showed no pathology.

Conclusion: These findings suggest that insulin and metformin may prevent and reverse some of pathologies caused by diabetes in major organs.

Keywords: Diabetes mellitus, metformin, kidney, lung, heart