Genotoxicity of Streptozotocin versus High Fat Diet-Induced Hyperglycemia in Adult Albino Rat Myocardium

Abstract

Background: Hyperglycemia has detrimental systemic and cardiac effects by increasing oxidative stress and advanced glycation end products (AGE). Prolonged hyperglycemia-induced DNA damage in various tissues. Aim: To compare the hyperglycemia-induced genotoxicity of STZ versus a high-fat diet (HFD) on rat myocardial tissue. Methods: Sixty-six adult male rats were allocated randomly into 3 groups of 22 rats each; Group I was maintained on a standard chow diet, Group II where rats were injected with STZ (40 mg/kg, intraperitoneally) for 5 consecutive days, and Group III where rats were fed HFD for 15 weeks. After reaching the hyperglycemic level (> 150 mg/dl), all rats were kept for 5 weeks on HFD to ensure the occurrence of DNA damage. Rats were euthanized and sacrificed at the end of the experiment. Blood samples were collected from the tail vein. The heart was excised carefully and processed for histological (Hematoxylin & eosin) and immunohistochemical staining (?H2AX). Results: The HFD group's serum levels were significantly higher for NO and MDA than the STZ group's serum levels, whereas GSH levels were lower. On histopathological examination, congested blood vessels, inflammatory cells, and spacing between cardiac muscle fibers were seen in Groups II and III. Regarding ?H2AX immunostaining, the reaction was marked in Group III as compared with Group II. Conclusion: Hyperglycemia induced deteriorative changes in the myocardial tissue. HFD-induced hyperglycemia produced much genotoxic damage to the myocardium. This could be related to its dramatic oxidative damage.