Improvement of a diet-induced model of hyperlipidemia in Wistar rats: Assessment of biochemical parameters, the thickness of the abdominal aorta and liver histology

Objectives: This study aimed to develop an improved and more reliable atherogenic diet-induced model of hyperlipidemia in Wistar rats for a better insight into pathophysiological changes and their effects on relevant biochemical and histological markers as well as on the thickness of the abdominal aorta. Methods: The study was conducted on a total number of 24 Wistar rats, three-month-old, weighing 180-230g that were divided into two groups: the standard rodent diet (SD) group (n = 12; 6 males and 6 females) in which rats were fed with commercially available standard rodent diet (SRD), and the atherogenic rodent diet (AD) group (n = 12; 6 males and 6 females) in which rats were fed with our mixture of atherogenic rodent diet (ARD) throughout the study period of 28 days. The body weight of rats was recorded weekly. The blood samples were collected by cardiac puncture and values of total cholesterol (TC) and triglycerides (TG) were determined at baseline, after the 14 days, and on the last day of the study, while other parameters high-density lipoprotein (HDL) cholesterol, lowdensity lipoprotein (LDL) cholesterol, non-HDL cholesterol, total protein (TP), glucose (GC), alanine transaminase (ALT), and aspartate transaminase (AST) were determined only on the last day of the study. The liver and abdominal aorta were collected after sacrifice and stored for further analysis. Results: Feeding rats with an ARD for 14 days resulted in the successful development of hyperlipidemia, as the TC and TG values were significantly increased (p < 0.05). Further feeding with an ARD for a total of 28 days resulted in significantly increased levels of TC, TG, LDL, non-HDL, and decreased levels of HDL compared to rats fed with SRD (p < 0.05). Greater risk predispositions for CVDs were documented for rats in the AD group, due to the significant increase in AI and LDL/HDL ratio compared to the SD group (p < 0.05). Conclusion: Obtained lipid profile and predictors confirm the establishment of a diet-induced model of hyperlipidemia in Wistar rats and prove the suitability of our model for future testing and proving the effectiveness of lipid-lowering agents.