The effects of quercetin on lipid profile, inflammatory biomarkers and ACE2 in a dyslipidaemic rabbit model

Dyslipidaemia is a major cardiovascular risk factor associated with elevated low-density lipoprotein (LDL) cholesterol and triglyceride levels. While statins are the primary treatment, inflammation remains a significant predictor of cardiovascular events, highlighting the need for adjunctive therapies targeting both lipids and inflammation. Quercetin, a flavonoid with antioxidant and antiinflammatory effects, has shown promise in preclinical models, although clinical results are mixed. This study investigates the effects of quercetin on lipid profiles, inflammatory biomarkers (bradykinin, C-reactive protein [CRP], interleukin-6 [IL-6]) and angiotensin-converting enzyme 2 (ACE2) levels in a rabbit model of dyslipidaemia, exploring its potential as an adjunctive therapy for dyslipidaemia.

Twenty male New Zealand White rabbits were randomly assigned to four groups (n=4): control, high-fat diet (HFD), HFD with quercetin (20 mg/kg/day), and HFD with atorvastatin (0.43 mg/kg/day, positive control). Rabbits received either a standard or HFD (1.2% cholesterol, 10% coconut oil) alone or HFD with quercetin or atorvastatin co-administered orally for 12 weeks. Blood samples were collected pre- and posttreatment for serum analysis. Body weight was measured weekly, and serum lipid profiles (total cholesterol, triglycerides, high-density lipoprotein [HDL], and LDL) were measured post-treatment. Serum levels of bradykinin, IL-6, CRP, and ACE2 pre- and post-treatment were quantified using enzyme-linked immunosorbent assay.

The HFD significantly increased body weight, total cholesterol, triglycerides, and LDL cholesterol in rabbits, while atorvastatin and quercetin co-treatments effectively reduced total and LDL cholesterol levels (p < 0.05) but had no impact on body weight. Neither HFD nor treatments significantly altered HDL cholesterol, bradykinin, IL-6, CRP, or ACE2 levels after 12 weeks. Changes in these inflammatory and enzymatic markers from pre-treatment to post-treatment were also not significant across groups.

Quercetin demonstrated lipid-lowering effects, particularly on total and LDL cholesterol, in a rabbit model of dyslipidaemia. However, it did not significantly affect systemic inflammatory or enzymatic markers. These findings suggest potential lipid-lowering effects independent of inflammation. While quercetin was not superior to atorvastatin, it shows promise as a natural adjunct or alternative therapy.