| Objective:The aim of the study is to evaluate the expression of heat shock protein-22(HSP22) in atherosclerotic Apo E-deficient(Apo E-/-) mice influenced by peroxisome proliferator-activated receptor-?(PPAR?) agonists pioglitazone(P io), and discuss the role of HSP22.Methods:1. Total thirty-six 8-9 weeks-old Apo E-/- male mice were used. They were randomly divided into four groups: the control group, the controlled intervention group, the model group and the model intervention group. The control group and the controlled intervention group were fed on normal diet, while the model group and the model intervention group were fed on high- fat diet(HFD). Pio was administered to mice from 5th week in intervention group. Other groups were administered by saline. All these mice were fed for 12 weeks to establish atherosclerosis models and intervened by gavage for 8 weeks.2. The weight of all mice was recorded per week. The lipid levels were measured at baseline and the end of the intervention, includ ing total cholesterol(TC), triglyceride(TG), low-density lipoprotein cholesterol(LDL-C) and high-density lipoprotein cholesterol(HDL-C). And the fasting blood glucose was detected at the end of the intervention.3. The O il Red O staining of the wall from Apo E-/- mice aortas and hematoxylin and eosin(HE) staining of Apo E-/- mice aortic arch and root were used to measure the atherosclerotic lesion burdens.4. The expressions of HSP22 protein in aortas were examined by western blot(WB) and immunohistochemistry(IHC) and the expressions of PPAR?, endothelial nitric oxide synthase(e NOS), p-e NOS(ser1177) and intercellular adhesion molecule-1(ICAM-1) protein were examined by WB. The serum interleukin-6(IL-6) levels were measured using an ELISA kit specific to mice IL-6.Results:1. The changes of lipid levels, the fasting blood glucose(1) The baseline lipid levels were no difference in all groups(P>0.05);(2) The lipid at the end of intervention: TC, LDL-C in model group and model intervention group were significantly increased compared with the control group(P<0.01), and HDL-C decreased significantly(P<0.01). The serum levels of TC and LDL-C in model intervention group were decreased significantly compared with model group(TC : P<0.05, LDL-C : P<0.01), and HDL-C increased significantly(P<0.01).(3) The fasting blood glucose at the end of intervention: the fasting blood glucose in model group and model intervention group increased significantly compared with the control group(P<0.01), while no obvious changes observed between model group and model intervention group.2. Histopathological observationHE staining of aortic root showed that apparent atherosclerotic plaque burdens could be seen in model group and model intervention group when compared with the control group(P<0.01), while the atherosclerotic plaque in model intervention group were notably reduced than model group(P<0.01). And the atherosclerotic lesions in whole aorta detected by the Oil Red O staining showed the same trend.3. The expression of PPAR?The expression of PPAR? protein in aorta in the model group were increased significantly compared with the control group(P<0.01), and after pioglitazone treatment, its expression were further increased compared with model group and control group, respectively(P<0.01).4. The expression of HSP22The expression of HSP22 protein in aorta examined by WB and IHC in model group and model intervention group were significantly increased compared with the control group(P<0.01), while its expression in model intervention group were significantly decreased compared with model group(P<0.01).5. The expressions of e NOS and p-e NOSThe expressions of e NOS and p-e NOS protein in aorta in model group were significantly decreased compared with the control group(P<0.05), while their expressions in model intervention group were significantly decreased compared with model group(P<0.05).6. The expression of ICAM-1The expression of ICAM-1 protein in aorta in model group and model intervention group were significantly increased compared with the control group(P<0.01), while its expression in model intervention group were significantly decreased compared with model group(P<0.01).7. The serum IL-6 levelsThe concentrations of serum IL-6 in model group were increased significantly compared with control group(P<0.01), and its concentrations in model intervention group were decreased significantly compared with model group(P<0.01).Conclusion:1. High fat diet can upregulate the expressions of PPAR? and HSP22, down-regulate the expressions of e NOS and p-e NOS, upregulate the expression of ICAM-1, and promote atherosclerosis.2. Pioglitazone can increase the expressions of e NOS and p-e NOS, decrease the expressions of ICAM-1 and HSP22 in the aorta after activating PPAR?, and inhibit the formation of atherosclerotic plaque. |
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