The effects of cinnamaldehyde (CIN), a commonly consumed food flavor, against high-cholesterol diet (HCD)-induced vascular damage in rabbits were evaluated. Male New Zealand rabbits (n = 24) were allocated to four groups at random: control, fed with standard rabbit chow; CIN, fed with standard diet and administered CIN; HCD, fed with 1% cholesterol-enriched diet; and HCD-CIN, fed with HCD and treated with CIN. CIN was orally given at a dose of (10 mg/kg/day) concomitantly with each diet type from day 1 until the termination of the experimental protocol (4 weeks). HCD elicited significant elevations in serum levels of total cholesterol (TC), triglycerides (TGs), and high- and low-density lipoprotein cholesterol (HDL-C and LDL-C, respectively) compared with control rabbits. Moreover, aortic levels of nitric oxide metabolites (NOx) and antioxidant enzyme activities were significantly lower, while aortic levels of malondialdehyde (MDA) and myeloperoxidase (MPO) activity were significantly higher, in HCD-fed rabbits relative to control animals. CIN administration mitigated or completely reversed HCD-induced metabolic alterations, vascular oxidative stress, and inflammation. Moreover, CIN ameliorated HCD-induced vascular functional and structural irregularities. Aortic rings from HCD-CIN group showed improved relaxation to acetylcholine compared to aortas from HCD group. Moreover, CIN decreased atherosclerotic lipid deposition and intima/media (I/M) ratio of HCD aortas. CIN-mediated effects might be related to its ability to attenuate the elevated aortic mRNA expression of cholesteryl ester transfer protein (CETP) and MPO in HCD group. Interestingly, the vasculoprotective effects of CIN treatment in the current study do not seem to be mediated via Nrf2-dependent mechanisms. In conclusion, CIN may mitigate the development of atherosclerosis in hypercholestrolemic rabbits via cholesterol-lowering, antiinflammatory and antioxidant activities.

No abstract

The present study aimed to determine the possible beneficial effects of dimethyl fumarate (DMF) against oxidative stress and inflammation in hypercholesterolemic rabbits. Twenty four New Zealand male rabbits were randomly allocated into 4 groups as the following: Group I (control): rabbits received standard rabbit chow; Group II high cholesterol diet (HCD): rabbits received 1% cholesterol-enriched chow for 4 weeks; Group III (HCD-DMF): rabbits received 1% cholesterol-enriched chow and administered DMF (12.5 mg/kg/day, orally) for 4 weeks; Group IV (DMF): rabbits received standard chow plus DMF (12.5 mg/kg/day, orally) for 4 weeks. At the end of experiment (day 30), blood samples were collected for measuring serum total cholesterol (TC), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C) and C-reactive protein (CRP). In addition, the aorta was removed for measurement of malondialdehyde (MDA), superoxide dismutase (SOD), mRNA expression of cholesteryl ester transfer protein (CETP) and histological assessment of intima/media (I/M) ratio. HCD-fed rabbits showed significant increases in TGs, TC, low-density lipoprotein cholesterol (LDL-C), aortic MDA and aortic I/M ratio levels while they significantly exhibited a reduced SOD level relative to control animals. Moreover, HCD rabbits demonstrated upregulated mRNA expression of CETP. DMF administration significantly decreased HCD-induced elevations in serum TC and LDL-C. Additionally, DMF decreased aortic level of MDA while increased SOD level. Moreover, DMF significantly downregulated mRNA expression of CETP and reduced the elevation in I/M ratio. In conclusion, this study suggests that DMF has the ability to improve HCD-induced vascular irregularities, possibly via its anti-inflammatory and antioxidant effect.