Background and purpose The present study was aimed to evaluate lipid-lowering and anti-atherogenic effect of an intravenous (IV) curcumin in the rabbit fed high cholesterol diet (HCD). Methods New Zealand white male rabbits (4–6 months old, n=25, weight 2.286±0.256 kg)were fed on a normal chow enriched with 0.5% (w/w) cholesterol for 5 weeks. Atherosclerotic rabbits were randomly divided into three group, including a control group receiving intravenous (IV) injection of saline buffer, two treatment groups receiving IV injection of curcumin at two different dosages, 1and 10 mg/kg/week, for 4 weeks. Blood samples were collected from fasted rabbits at pre- (week 5) and post-treatment (week 11) points for analysis of serum lipid levels, including low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), triglyceride (TG), and total cholesterol (TC). Aortic arch atherosclerotic lesions were assessed using hematoxylin and eosin (H&E) staining. Results To evaluate curcumin's effects on the hyperlipidemic states and atherosclerosis plaque, HCD-fed rabbits were weekly treated with the injectable curcumin at the low (1mg/kg/week) and high (10 mg/kg/week) doses by 4 weeks. At week 4 in compared with the control group, low-dose curcumin could reduce serum levels of LDL-c, HDL-c, TG, and TC by −6.22% ±1.77, −35.24% ±12.49, −29.84% ±10.14, −14.19% ±5.19, respectively. In the case of high-dose curcumin, serum levels of LDL-c, HDL-c, TG, and TC were changed by −44.36%±3.24, 14.05% ±6.39, −25.92% ±5.57, −56.59% ±10.22, respectively, when compared with the control group at week 4. Low-dose curcumin after 4 weeks' treatment could reduce serum levels LDL-c, HDL-c, TG, and TC up to 103±28 mg/dL, 18.33±4.66 mg/dL, 97.5±31 mg/dL, and 356.5±19.5 mg/dL, respectively, when compared with the base line levels (week 0). High-dose curcumin after 4 weeks' treatment could decrease serum levels of LDL-c, HDL-c, TG, HDL-c, and TC up to 207±17.04 mg/dL, 15.5±0.5 mg/dL, 333±40 mg/dL, and 514.5±22.23 mg/dL, respectively (Figure). H&E staining declared that atherosclerotic lesion grades were significantly lower in the curcumin-treated groups than the control group. Changes of lipids in rabbits on curcumin Conclusions The injectable curcumin at the low (1mg/kg) and high (10 mg/kg) could significantly improve dyslipidemia and alleviate atherosclerotic lesion in HCD-induced atherosclerotic rabbits.

Curcumin has a potent antioxidant and anti-inflammatory properties that may suppress inflammatory component of atherosclerosis. It has been demonstrated that curcumin derivatives can reduce the formation of arterial fatty streaks in cholesterol-fed rabbits. Therefore in this study we evaluated the protective effects of Curcumin on the progression of atherosclerosis. 20 mature rabbits were included for this study; they were randomly divided into four groups each of 5. Group 1: (normal control) were fed corn pellets diet and tab water, group 2: (high cholesterol diet control) were kept on cholesterol rich diet (2% cholesterol) and tab water. Group 3: (cholesterol and rosuvastatin treated group) were kept on cholesterol rich diet (2% cholesterol) and 2.5 mg/kg/day Rosuvastatin dispersed in DW and given orally, group 4: (cholesterol and curcumin treated group) were kept on cholesterol rich diet (2% cholesterol) and 0.2% curcumin added with corn pellets. The study continued for 12 weeks then assessment of serum level of high sensitive C-reactive protein, ICAM1, VCAM1 and PCSK9 was carried out at the end of the study. Total antioxidant activity of curcumin was also determined. Histopathological examination of aortic tissues for atherosclerotic changes was also carried out. Atherogenic (cholesterol rich diet) induced an increment in serum level of TC, LDL, VLDL and TG with concomitant decrement in serum level of HDL and increased atherogenic index. Treatment with curcumin produced substantial reduction in serum TC, LDL, TG with no effect on HDL level thus decreased atherogenic index. Rabbits treated with curcumin showed a significant reduction in the serum level of high sensitive C-reactive protein, ICAM1, VCAM, PCSK9 serum expression and aortic total antioxidant capacity. Curcumin has a potent anti-inflammatory and anti-oxidant effects against atherosclerosis so exerts a protective role by decreasing lipid oxidation and inflammatory markers.

Objective: To evaluate the potential protective effect of irbesartan on atherosclerotic progression using rosuvastatin as a positive control. Methods: Twenty local domestic rabbits were randomly divided into four groups, five rabbits per each group. The first group (I), rabbits were receiving normal diet; the second group (II), rabbits were receiving 2 % cholesterol diet; the third group (III), rabbits were receiving rosuvastatin and 2% cholesterol diet and; the fourth group (IV), rabbit were receiving irbesartan and 2% cholesterol diet. Serum level of cholesterol, triglycerides, LDL, VLDL and HDL were determined after 12 weeks of the study. Serum level of high sensitive C-reactive protein, ICAM1and VCAM1 were measured after 12 weeks of the study. Total antioxidant activity was also determined. Aortic tissue sent for histopathological examination of atherosclerosis lesion. Result: Data of this study have showed that atherogenic diet caused an increase in serum level of TC, LDL, VLDL and TG and a decrease in serum level of HDL. Treatment of rabbits with irbesartan caused substantial decrease in serum lipid profile compared with untreated rabbit receiving atherogenic diet. No significant difference was seen between irbesartan- and rosuvastatin-treated rabbits in all lipid parameters measured with the exception that the HDL level in rosuvastatin-treated rabbits was significantly higher than that of irbesartan-treated rabbits. Rabbit treated with irbesartan showed a significant decrease in the serum level of high sensitive C-reactive protein, ICAM1, VCAM1 and aortic total antioxidant capacity when compared with untreated group. No significant difference was seen between irbesartan- and rosuvastatin-treated rabbits in all these inflammatory parameters measured. Histopathological examination showed that irbesartan decreased atherogenic lesion significantly when compared with untreated rabbits. Conclusion: Irbesartan has a potential protective effect against atherosclerosis via decreasing lipid oxidation and inflammatory mediators. In terms of lipid lowering and anti-inflammatory effects, irebsartan has similar pattern of effectiveness to rosuvastatin.