Thymol decreases apoptosis and carotid inflammation induced by hypercholesterolemia through a discount in oxidative stress

Atherosclerosis sclerosis is a chronic inflammatory disease that can lead to cardiovascular and cerebrovascular disorders that are generally along with hypercholesterolemia and oxidative stress. Various surveys have shown that thymol is a polyphenolic compound with anti-inflammatory and antioxidant properties. This study aimed to investigate the anti-inflammatory and antiapoptotic effects of thymol on carotid tissue of hypercholesterolemic rats.
Forty male Wistar rats were randomly divided into 4 groups with 10 members each (n = 10): a control group with a normal diet (ND), a group with a high-cholesterol (2%) diet (HD), a group with a high-cholesterol diet combined with thymol (24 mg/kg HD T), and a group with a thymol diet (T). After preparing serum from peripheral blood of rats, lipid measurements were obtained, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), by using a colorimetric method; the levels of oxidized LDL (OxLDL) were obtained through enzyme-linked immunosorbent assay (ELISA). The activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) antioxidant enzymes, as well as the concentrations of malondialdehyde (MDA) and serum total antioxidant capacity (TAC), were determined with the use of colorimetric methods. The protein expressions of Bcl2 and cleaved caspase 3 and the phosphorylation of p38 mitogen-activated protein kinase (MAPK) in rat carotid tissue were determined by an immunoblotting method.
The rats fed with a high-cholesterol diet for 8 weeks increased TC and OxLDL in HD group compared with the ND group (P The results of this study indicate that thymol significantly decreases the expression of inflammatory and apoptotic proteins in carotid tissue. However, this decrease is probably not mediated by an effect on lipid metabolism because thymol decreases the total level of cholesterol but has no significant effect on the LDL-C level as the atherogenic index. In addition, thymol possibly exerts an antioxidant effect without the direct involvement of antioxidant enzymes.