[Effect of mild moxibustion at 45 ℃ with different durations at "Zusanli" （ST36） on the inflammatory factors in the abdominal aorta of hyperlipidemia rats]

Abstract

Objective: To investigate the effects of mild moxibustion at 45°C on the chronic inflammatory response of the abdominal aorta in rats with hyperlipidemia and the effects of different moxibustion durations.

Methods: Thirty-six SD rats were randomly divided into the following groups： blank control group (2 weeks), model group (2 weeks), moxibustion group (2 weeks), blank group (4 weeks), model group (4 weeks), and moxibustion group (4 weeks). A model of hyperlipidemia with chronic inflammation was established through high-fat diet feeding for 8 weeks. Rats in the moxibustion groups received mild moxibustion treatment at bilateral "Zusanli"(ST36) at 45 °C, 10 min every time, once a day, for consecutive 2 or 4 weeks. The morphology of the abdominal aorta in each group was observed by using HE staining. Contents of serum total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), oxidized low-density lipoprotein (ox-LDL), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), endothelin-1 (ET-1) and the contents of nitric oxide (NO), ox-LDL, and ET-1 in the abdominal aorta were measured by using ELISA. Protein and mRNA expressions of IL-6 and TNF-α in the abdominal aorta of rats in each group were detected by using Western blot and real-time fluorescence quantitative PCR respectively. The positive expression of IL-6 in the abdominal aorta of rats was detected by Immunofluorescence.

Results: Compared to the blank control group, rats in the model group had increased contents of LDL, TC, TG, ox-LDL, VCAM-1, ICAM-1, IL-6, TNF-α, and ET-1 in the serum, increased contents of ox-LDL and ET-1 in the abdominal aorta, increased protein and mRNA expressions of IL-6 and TNF-α in the abdominal aorta(P<0.01, P<0.05, P<0.001), with decreased HDL content in the serum, decreased NO content in the abdominal aorta (P<0.01, P<0.05), as well as dark pink abdominal aorta, rough textures in the adventitia, media, and intima, and rough endothelial layer. Compared to the model group(2 weeks), LDL, ICAM-1, ET-1 contents in the serum, ox-LDL content in the abdominal aorta were decreased(P<0.05), while serum IL-6 and TNF-α contents, and NO content in the abdominal aorta were significantly increased(P<0.01, P<0.05), with smoother vascular walls, and relatively clear nucleus and surrounding tissue structures of abdominal aorta in the moxibustion group(2 weeks). Compared to the model group(4 weeks), contents of LDL, TC, TG, VCAM-1, ICAM-1, IL-6, TNF-α, ox-LDL, and ET-1 in the serum, ox-LDL and ET-1 contents in abdominal aorta, protein and mRNA expressions of IL-6 and TNF-α in the abdominal aorta were significantly decreased(P<0.05, P<0.01), while HDL content in the serum and NO content in the abdominal aorta were significantly increased(P<0.05, P<0.01), with smoother vascular walls, and relatively clear nucleus and surrounding tissue structures of abdominal aorta in the moxibustion group(4 weeks). In addition, content of HDL in the serum were significantly increased(P<0.05), while TNF-α content in the serum, protein expression of IL-6 in the abdominal aorta were significantly decreased (P<0.001, P<0.05), with smoother vascular walls, and clearer nucleus and surrounding tissue structures of abdominal aorta in the moxibustion group(4 weeks), in comparison with the moxibustion group(2 weeks).

Conclusion: Mild moxibustion of 45 °C at ST36 can improve vascular endothelial damage and inflammatory response induced by high-fat diet by regulating serum lipids, vascular tone, adhesion molecules, and inflammatory factors, of which the effect of moxibustion intervention for 4 weeks is more significant.

Keywords: Abdominal aorta; Chronic inflammatory response; Hyperlipidemia; Moxibustion; Moxibustion duration; Zusanli （ST36）.