Impact of Low and High Dose of Streptozotocin on the Levels of Antioxidants and Liver Enzymes in Rats

Background: Streptozotocin (STZ) is the most prominent diabetogenic chemical that is widely used in experimental animals for creating animal models of diabetes. Obtaining valid data from STZ-based animal models of diabetes depends on the correct preparation and use of STZ. Aims: The current study aims to investigate the impact of streptozotocin injected at different doses on the levels of antioxidants and liver enzymes in rats. Materials and methods: A total of 35 female rats were purchased, acclimated, and divided randomly and equally into 5 groups; NCG (as non-injected-negative control), EG1 (streptozotocin-injected at 50mg/kg.BW), EG2 (streptozotocin-injected at 100mg/kg.BW), EG3 (streptozotocin-injected at 150mg/kg.BW) and EG4 (streptozotocin-injected at 200mg/kg.BW). After 72 hours of streptozotocin injection, blood samples were collected directly from heart, and the obtained sera were tested quantitatively by ELISA to measurement the concentrations of antioxidants (catalase, glutathione peroxidase [GPX], and superoxide dismutase [SOD]) as well as the liver enzymes (alkaline phosphatase [ALP], alanine aminotransferase [ALT], and aspartate aminotransferase [AST]). Results: In comparison to values of NCG, the findings of all experimentally groups (EG1, EG2, EG3, and EG4) were shown a significant decrease in values antioxidants (catalase, GPX, and SOD) and a significant elevation in values of liver enzymes (ALP, ALT, and AST). Among the experimentally study groups, the highest values of antioxidants were detected in EG1 while the lowest was seen in EG4. In contrast, the lowest value of liver enzymes was observed in EG1 and the highest in EG4. Conclusion: This study revealed the negative effect of streptozotocin on targeted biomarkers, suggesting its role in the development of oxidative stress and related complications in a number of body tissues. Subsequently, the impact is dose-dependent since the high dose of streptozotocin causes severe alteration in the values of all antioxidants and liver enzymes. However, additional studies are of great importance to estimate the effect of streptozotocin on different enzymes, hormones and body markers even tissues and organs.