Effects of moxibustion with wheat-grain size cone at "Zusanli" (ST 36) on vascular injury and oxidative stress in high-fat diet rats through mTOR/HIF-1α/VEGF signaling pathway.

OBJECTIVES To explore the effect mechanism of moxibustion with wheat-grain size cone at "Zusanli" (ST 36) on vascular injury and oxidative stress in hyperlipidemia through mammalian target of rapamycin (mTOR)/hypoxia inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) signaling pathway. METHODS Forty healthy male SD rats with SPF grade were randomly divided into a normal group, a model group, a moxibustion group, and an inhibitor group, with 10 rats in each one. The hyperlipidemia model was established by feeding a high-fat diet for 8 weeks in rats of the model group, the moxibustion group and the inhibitor group. The moxibustion with wheat-grain size cone was delivered at bilateral "Zusanli" (ST 36) of each rat in the moxibustion group and the inhibitor group, with 3 cones on each acupoint in each intervention, once daily for 4 weeks. In the inhibitor group, before each intervention with moxibustion, rapamycin solution was injected intraperitoneally, 2.0 mg/kg. After modeling and intervention, using ELISA, the levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) in the serum of rats were determined. After intervention, with HE staining and oil red O staining adopted, the abdominal aortic morphology and peripheral lipid deposition were observed. Separately, using WST-1, TBA and micro-plate method, the superoxide dismutase (SOD) activity and the levels of malondialdehyde (MDA) and nitric oxide (NO) in the serum were detected. The protein expression of mTOR, HIF-1α and VEGF in abdominal aorta were measured by Western blot method. RESULTS Compared with those in the normal group, the levels of TC, TG and LDL-C increased (P<0.01) and HDL-C decreased (P<0.01) in the serum of the rats in the model group, the moxibustion group and the inhibitor group after model establishment. When compared with the normal group after intervention, in the model group, the serum levels of TC, TG, LDL-C and MDA increased (P<0.01), HDL-C level, SOD activity and NO level were reduced (P<0.01); the cell structure of the abdominal arota was abnormal, the peripheral lipids deposited seriously; and the protein expression of mTOR, HIF-1α and VEGF of abdominal aorta was elevated (P<0.01, P<0.05). In comparison with the model group, the levels of TC, TG, LDL-C and MDA were reduced (P<0.01), HDL-C levels, SOD activities and NO levels elevated (P<0.01, P<0.05), as well as the protein expression of mTOR, HIF-1α and VEGF of abdominal aorta (P<0.01, P<0.05) in the moxibustion group and the inhibitor group; besides, the vascular structure was ameliorated and the lipid deposition reduced in the moxibustion group, while, the vascular structure was still abnormal and the lipid deposition declined in the inhibitor group. When compared with the inhibitor group, the serum SOD activity and NO level increased (P<0.05) and MDA decreased (P<0.05); and the protein expression of mTOR, HIF-1α and VEGF of abdominal aorta was elevated (P<0.01, P<0.05) in the moxibustion group. CONCLUSIONS The vascular injury due to hyperlipidemia is repaired by moxibustion with wheat-grain size cone at "Zusanli" (ST 36) through ameliorating oxidative stress, which is associated potentially with the modulation of mTOR/HIF-1α/VEGF signaling pathway.