Ameliorative effects of tallow and olive oil on hyperlipidemia-induced atherogenesis in male albino rats

Hyperlipidemia and atherosclerosis are the major contributors to cardiovascular morbidity and mortality worldwide. This study aimed to evaluate the ameliorative effects of sheep tallow (SHT), bovine tallow (BT), and olive oil (OL) on lipid profiles, oxidative stress, inflammation, and atherosclerotic lesions in a rat model of atherogenesis induced by a high-fat diet. Rat groups received an atherogenic diet (AGD) containing cholesterol, cholic acid, and thiouracil for 12 weeks to induce atherosclerosis, followed by SHT, BT, OL, or simvastatin (positive control, PC) for another 12 weeks. Atherogenicity and oxidative toxicity were assessed via biochemical and histopathological analyses. C18:0 (stearic acid) was the most abundant fatty acid in BT (34.648%), followed by SHT (7.064%) and OL (3.535%). C18:1 (oleic acid) was highest in OL (67.949%), followed by SHT (43.737%) and BT (26.325%). C18:2t + 1 (trans-linoleic acid) was present at 11.434% in OL. AGD induced significant dyslipidemia, oxidative stress, and aortic and cardiac tissue damage in rats. Supplementation with tallow or olive oil significantly reduced total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), malondialdehyde (MDA), and C-reactive protein (CRP) levels, whereas the same supplementation significantly increased high-density lipoprotein cholesterol (HDL-C) and total antioxidant (TAO) levels (p < 0.001). Additionally, the atherogenic index (AI) was significantly reduced (p < 0.0001) in all treated groups, indicating protection against hyperlipidemic-induced oxidative stress and atherogenesis. Histopathological analysis revealed partial to evident regression of atherosclerotic changes, with the most pronounced effects observed in the OL group, followed by the SHT and BT groups. The high C18:1 (oleic acid) content in OL and the high C18:0 (stearic acid) content in BT may underlie their cardioprotective effects. OL, SHT, and BT demonstrated lipid-lowering, antioxidant, and anti-inflammatory properties that contributed to the regression of diet-induced atherosclerosis in rats. These findings suggest that both plant-based olive oil and animal-derived tallows may exert cardioprotective effects depending on their fatty acid composition in this rat model of atherogenesis.