ABSTRACT
Objective To investigate the protective effect of high-density lipoprotein (HDL) on the mice cardiac myocytes induced by oxygen and glucose deprivation (OGD).Methods Cardiac cells of primary scavenger receptor-B1 knockout mice (SR-B1-/-) and normal C57 mice (SR-B1+/+) were obtained by protease digestion and differential adhesion method. ① The two kinds of cells were divided into normal control group (Con group), OGD group, OGD+HDL group. Propidium iodide (PI) staining were used to determine the necrosis of cardiac myocytes. ② SR-B1+/+cardiac cells were divided into Con group, OGD group, OGD+HDL group, and phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) inhibitor LY294002 group. PI staining were used to determine the necrosis of cardiac myocytes. TUNEL staining was used to determine the cell apoptosis. The kit was used to determine the contents of MB isoenzyme of creatine kinase (CK-MB) and lactate dehydrogenase (LDH) in the culture medium supernatant. The expressions of SR-B1 and Akt protein were determined by Western Blot.Results ① In SR-B1+/+ cardiomyocytes, HDL could inhibit cell necrosis induced by OGD. There was no protective effect of HDL on OGD in the SR-B1-/- cardiomyocytes.② The study of SR-B1+/+ cells was showed that compared with Con group, necrotic cells were significantly increased and cell activity were significantly decreased, the cell viability were significantly decreased, the contents of LDH and CK-MB in supernatant were significantly increased, the expressions of phosphorylated Akt (p-Akt) and SR-B1 were significantly decreased in OGD group. Compared with OGD group, the number of necrotic cells in the OGD+HDL group was significantly decreased [PI positive cells rate: (26.71±5.94)％ vs. (64.24±18.34)％], the cell activity was significantly increased [(63.84±6.95)％ vs. (26.71±5.13)％], the contents of LDH and CK-MB in supernatant were significantly decreased [LDH (U/L): 896.3±161.5 vs. 1568.3±243.5, CK-MB (U/L): 304.3±72.9 vs. 583.6±81.6], the expressions of p-Akt and SR-B1 were significantly increased (p-Akt/t-Akt: 0.84±0.13 vs. 0.18±0.06, SR-B1/β-actin: 1.23±0.19 vs. 0.09±0.02), with statistically significant differences (allP < 0.05). Compared with OGD+HDL group, necrotic cells in LY294002 group were increased, cell activity was decreased, LDH and CK-MB contents in supernatant were increased, p-Akt and SR-B1 expressions were decreased; there was no statistical difference between LY294002 group and OGD group. There was no significant difference in cell apoptosis among the 4 groups.Conclusions HDL has protective effect on the mice myocardial cells. The mechanism may be related with the up regulation of the expression of SR-B1 protein by the activation of PI3K/Akt pathway.
ABSTRACT
OBJECTIVE: To observe the effect of herbal-cake-separated moxibustion on blood lipid levels and expression of peroxisome proliferator-activated receptor γ (PPARγ) and scavenger receptor B 1 (SR-B 1) proteins and genes in liver of hyperlipidemia atherosclerosis rabbits, so as to explore its mechanism underlying anti-atherosclerosis formation. METHODS: Forty male New Zealand white rabbits were randomly divided into normal control, model, moxibustion and Simvastatin groups (n＝10 rabbits in each group). The hyperlipidemia atherosclerosis model was established by high cholesterol diet and propylthiouracil for 12 weeks. Herbal-cake-separated moxibustion was applied to "Juque" (CV 14), and bilateral "Tianshu" (ST 25), "Fenglong" (ST 40) (point group 1), and bilateral "Xinshu" (BL 15), "Ganshu" (BL 18) and "Pishu" (BL 20) (point group 2). The two groups of points were used alternately. Simvastatin (1.96 mg•kg－1•d－1) mixed in the forage was given to rabbits of the Simva-statin group. Both moxibustion and medication treatments were given once daily for continuous 4 weeks. Total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) levels in plasma were detected by using an automatic biochemistry analyzer. The expression levels of PPARγ and SR-B 1 proteins and genes in the hepatic tissue were determined by Western blot and reverse transcription-polymerase chain reaction, separately. RESULTS: After modeling, plasma TC, TG and LDL-C levels in the model group were significantly increased (P<0.01), and the levels of plasma HDL-C and hepatic PPARγ and SR-B 1 protein and mRNA expression were obviously down-regulated relevant to the normal group (P<0.01). Compared with the model group, plasma TC, TG and LDL-C levels were significantly decreased (P<0.01), and plasma HDL-C and hepatic PPARγ and SR-B 1 protein and mRNA levels were significantly up-regulated in the two treatment groups (P<0.01, P<0.05). CONCLUSION: Herbal-cake-separated moxibustion can regulate blood lipid levels and suppress hyperlipidemia-induced decrease of expression of hepatic PPARγ and SR-B 1 proteins and genes in hyperlipidemia atherosclerosis rabbits, which maybe contribute to its action in anti-atherosclerosis through promoting reversal of cholesterol.