Experimental study of the anti-atherosclerotic effect of demethylzeylasteral

This study aimed to confirm that atherosclerosis (AS) is a systemic immune-mediated chronic inflammatory disease and to investigate the anti-atherosclerotic effect of demethylzeylasteral by testing the immunocompetent cells and inflammatory mediators in the blood and atherosclerotic plaques of the rabbit model of AS. For this purpose, 60 male New Zealand white rabbits were given 150 g high-fat diet (1% cholesterol, 5% lard, and 15% egg yolk powder) daily for a total of 90 days. On day 61, the rabbits were randomly divided into the saline group (n=15), the rosuvastatin group (n=15), the low-dose demethylzeylasteral group (n=15), and the high-dose demethylzeylasteral group (n=15). The CD3⁺ T lymphocytes and the subsets CD4⁺, CD8⁺, and CD4⁺/CD8⁺, as well as the soluble interleukin-2 receptor (sIL-2R) were measured before and after the treatment. The contents of immunoglobulins IgG, IgA and IgM and the levels of complements C3 and C4 were also monitored. In addition, the level of anti-oxidized low-density lipoprotein (ox-LDL) antibody, the inflammatory cytokines tumor necrosis factor-α (TNF-α), IL-6 and metalloproteinase-9 (MMP-9), the blood lipids triglyceride (TG), total cholesterol (TC), LDL cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were measured, and the severity of plaque lesions was also evaluated. Our results showed that the saline group, the rosuvastatin group and the low-dose demethylzeylasteral group had significantly lower activated T lymphocyte parameters CD3⁺, CD4⁺, CD8⁺ and CD4⁺/CD8⁺ (P<0.05), and significantly higher levels of sIL-2R, immunoglobulins IgG, IgA and IgM, complements C3 and C4, anti-ox-LDL antibody, TNF-α, IL-6 and MMP-9 (P<0.01) when compared with the high-dose demethylzeylasteral group. Moreover, TG, TC, LDL-C contents were found significantly lower and their HDL-C contents were significantly higher in high-dose demethylzeylasteral group (P<0.01) as compared to the other three groups. Furthermore, Sudan staining and haematoxylin and eosin staining of the thoracic aorta showed that, after 30-day treatment, the high-dose demethylzeylasteral group had the smoothest intima and the lightest plaque lesions among the four groups. Based on these results, we concluded that AS is a systemic immune-mediated chronic inflammatory disease and the relatively high dose of demethylzeylasteral used in the treatment of atherosclerotic rabbits could significantly alleviate AS. This implies that demethylzeylasteral may be considered as a suitable drug for anti-immunization therapy.