Background: Hyperlipidemia is a well-established risk factor for cardiac damage, which can lead to cardiovascular diseases. Many studies have shown that Coenzyme Q10(CoQ10) protects against cardiac damage in vivo. The aim of this study was to investigate the possible protective effects of CoQ10 against cardiac damage in apolipoprotein E-deficient (ApoE^-/-) mice.

Methods: Eight-week-old male C57BL/6 and ApoE^-/- mice were randomly divided into four groups: C57BL/6 mice fed a normal diet (C57BL/6 group); C57BL/6 mice fed a normal diet + CoQ10 (C57BL/6 + CoQ10 group); ApoE^-/- mice fed a high-fat diet (ApoE^-/- HD group), and ApoE^-/- mice fed a high-fat diet + CoQ10 (ApoE^-/- HD + CoQ10 group). All groups were fed the different diets for 16 weeks. Blood samples were obtained from the inferior vena cava and collected in serum tubes. The samples were then stored at - 80 °C until used. Coronal sections of heart tissues were fixed in 10% formalin and then embedded in paraffin for histological evaluation. The remainder of the heart tissues was snap-frozen in liquid nitrogen for mRNA or immunohistochemical analysis.

Results: The metabolic parameters such as total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-c), and triglycerides (TG) levels were lower in ApoE^-/-HD + CoQ10 mice than in ApoE^-/- HD mice. There were significant pathophysiological changes (H&E, PAS, Masson and CD68 staining) in ApoE^-/- mice in the HD group compared with those in the HD + CoQ10 group. CoQ10 reduced HD-induced cardiac tissue damage via autophagy (p62 and LC3), as evidenced by immunoblotting, immunohistochemistry, and RT-qPCR. CoQ10 also inhibited inflammation (IL-6 and TNF-α) gene expression in ApoE^-/- mice.

Conclusions: These results indicate that CoQ10 is a potential therapeutic target for cardiac damage caused by hyperlipidemia.