Effect of mild moxibustion on SIRT1/NF-κB signaling in atherosclerotic rabbits

Abstract

To observe the effect of mild moxibustion on blood lipid, histopathological structure of the aortic arch, thoracic aortic silent information regulator 1 (SIRT1)/nuclear factor κB (NF-κB) signaling pathway in atherosclerosis (AS) rabbits, so as to explore its underlying mechanisms in improving AS. Sixty male rabbits were randomly divided into control group (n=12), model group(n=11), mild moxibustion group (n=11), mild moxibustion + blocker (blocker) group (n=12). The AS model was established by feeding the rabbits with high-fat forage for 8 weeks, followed by immune response damage. Mild moxibustion was applied to "Danzhong"(CV17), "Shenque"(CV8) and "Neiguan" (PC6, bilateral) and "Xuehai" (SP10, bilateral) for 30 min, once daily, 3 times a week for 4 weeks. Rabbits of the blocker group received intraperitoneal injection of EX527 (a selective inhibitor of SIRT1, 5 mg·kg-1·d-1) 30 min before moxibustion. Rabbits of the control and model groups were only grabbed and fixed without intervention. After the intervention, the contents of serum triglyceride (TG) and total cholesterol (TC) were determined by enzymatic method, and those of serum low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were determined by colorimetric method. The Sudan Ⅳ staining was employed to observe the histopathological structure of the aortic arch, and Western blot and fluorescence quantitative real time-PCR were used to detect the expressions of SIRT1 and NF-κB proteins and mRNAs in the thoracic aorta, respectively. Compared with the control group, the contents of serum TG, TC and LDL-C and the expression levels of NF-κB protein and mRNA were significantly increased (P<0.01, P<0.05), whereas the content of HDL-C and the expression of SIRT1 mRNA markedly decreased in the model group (P<0.01). After mild moxibustion, the contents of serum TG, TC, and LDL-C and the expression of NF-κB protein and mRNA were significantly down-regulated (P<0.01, P<0.05), while the content of HDL-C and the expression levels of SIRT1 protein and mRNA significantly up-regulated in the mild moxibustion group (P<0.05, P<0.01). There were no significant differences between the blocker and model groups in all the indexes (P>0.05). Compared with the mild moxibustion group, the serum TG, TC, and LDL-C contents and NF-κB protein expression were significantly increased (P<0.01, P<0.05), and HDL-C content and the expression of SIRT1 protein and mRNA significantly decreased (P<0.05, P<0.01) in the blocker group. Sudan Ⅳ staining showed vague structure of the aortic arch with obvious lipid infiltration in the model group, which was relatively milder in the mild moxibustion. Mild-moxibustion can reduce blood lipid levels and endothelial damage in atherosclerotic rabbits, which may be related to its function in regulating SIRT1/NF-κB signaling pathway.