Protective effect of melatonin on hyperglycemia-induced consequences in rats with insulin resistance

Oleksandra Kushnir; Iryna Yaremii; Volodymyr Vivsyannuk; Inna Buzdugan; Olga Bukach; Georgiy Prodanchuk; Oksana Iftoda

Oleksandra Kushnir Department of Bioorganic and Biological Chemistry and Clinical Biochemistry, Bukovynian State Medical University, Chernivtsi, Ukraine https://orcid.org/0000-0002-8011-6825
Iryna Yaremii Department of Bioorganic and Biological Chemistry and Clinical Biochemistry, Bukovynian State Medical University, Chernivtsi, Ukraine https://orcid.org/0000-0001-7969-345X
Volodymyr Vivsyannuk Department of Bioorganic and Biological Chemistry and Clinical Biochemistry, Bukovynian State Medical University, Chernivtsi, Ukraine https://orcid.org/0000-0003-4728-1500
Inna Buzdugan Department of Bioorganic and Biological Chemistry and Clinical Biochemistry, Bukovynian State Medical University, Chernivtsi, Ukraine https://orcid.org/0000-0002-4599-2360
Olga Bukach Department of Bioorganic and Biological Chemistry and Clinical Biochemistry, Bukovynian State Medical University, Chernivtsi, Ukraine https://orcid.org/0000-0001-7346-0559
Georgiy Prodanchuk Department of Bioorganic and Biological Chemistry and Clinical Biochemistry, Bukovynian State Medical University, Chernivtsi, Ukraine https://orcid.org/0000-0001-9498-0510
Oksana Iftoda Department of Bioorganic and Biological Chemistry and Clinical Biochemistry, Bukovynian State Medical University, Chernivtsi, Ukraine https://orcid.org/0000-0003-0175-6064

Keywords: melatonin, rats, blood, insulin resistance

Abstract

The aim of the study was to determine the effect of melatonin on the content of glucose, insulin, total lipids, total cholesterol, high-density lipoproteins (HDL) and pyruvate on the activity of pyruvate kinase (PK) in the blood of rats with insulin resistance (IR). 18-month-old outbred white male rats were divided into three groups: 1) control (intact); 2) rats with IR (daily subcutaneous administration of dexamethasone solution, dose of 0.125 mg/kg for 13 days); 3) IR rats that received metformin (intragastrically at a dose of 200 mg/kg per day); 4) IR rats were orally administered melatonin (dose of 10 mg/kg). Fasting blood glucose was measured using a glucometer, and serum insulin was measured using an immunochemiluminescent analyzer on day 14. The IR index was calculated using the homeostasis model assessment (HOMA) index for IR. Parameters were determined in the blood using standard methods. Statistical processing of the results was performed using IBM SPSS Statistics 21, and according to our data, glucose and pyruvate levels in IR rats increased by 170% and 173%, respectively, which was accompanied by an increase in insulin levels and the HOMA-IR index by 5.8 times and 14 times respectively compared to controls. Daily treatment with metformin and melatonin reduced fasting glucose levels by 34% and 58%, respectively, compared with control. Metformin administration reduced insulin levels and HOMA-IR by 65% and 77%, and melatonin administration reduced these values by 78% and 90%, respectively, compared with control. Melatonin administration in IR rats resulted in the normalization of all investigated indexes.