| BackgroundAtherosclerosis is the pathological basis for many important cardiovascular disease development, lipid accumulation in the blood vessel walls, increasing the fiber content of the vessel wall and chronic inflammation as the main feature. Inflammation hypothesis is the deciding factor in the pathogenesis of AS, through the formation and development of AS. Recent studies suggest that the immune response, including innate and acquired immune mechanisms play an important role in the formation and development of AS. Inflammation and immune responses within the atherosclerotic plaque plaque surface enhancement allows the fibrous cap thinning, increased plaque instability. Therefore, the intensity of the inflammatory response of atherosclerotic plaques is an important factor in the structural instability of the functional instability affecting progress, regulate the immune response is to maintain the stability of the important aspects of vulnerable plaque. All-trans retinoic acid(all-trans-ratinoic acid, ATRA) is a natural derivative of vitamin A major recent study found that, ATRA has mediated cell differentiation, proliferation, apoptosis and regulation of the immune and other. Statins have been shown to lipid inflammatory, improve endothelial function, stabilize and reverse atherosclerotic plaque and so widely used in clinical practice. This study was to establish a New Zealand white rabbit model of carotid atherosclerosis by high fat diet method, simultaneous simvastatin and ATRA drug intervention, and then observe the inhibition of simvastatin and ATRA on carotid atherosclerosis in the inflammatory response investigate whether ATRA by regulating TGF-and its downstream pathways to inhibit inflammation, improve and stabilize atherosclerotic plaques role in providing a theoretical basis for clinical use.ObjectiveConstruction of rabbit model of carotid atherosclerosis by high-fat diet, observation of all-trans retinoic acid(ATRA) compared with simvastatin on blood lipids and carotid atherosclerosis and inflammatory lesions in the inhibition of cell proliferation by inflammation downstream molecular studies of regulatory T cells, and to explore the role of ATRA treatment based on TGF- / Smad pathway ATRA improve early carotid atherosclerosis.Method1 The 34 healthy purebred male New Zealand white rabbits were randomly divided into four groups: normal control group(n = 6), model control group(n = 8), simvastatin treatment group(n = 10), ATRA treatment group(n = 10). Normal control group was given normal diet, the rest of the group was given high-fat diet. After 4 weeks, the simvastatin treatment group received to simvastatin according to 2mg / kg · d computing gavage, ATRA treatment group received ATRA 20 mg / d ogavaged, model control group did not use any drugs, but to gavaged the same amount of normal saline.2 Experiment 12 weeks end from heart blood, after stew few minutes at room temperature, centrifugation for serum, using automatic biochemical analyzer analyzed the concentrations of serum total cholesterol(TC), triglyceride(TG), low density lipoprotein cholesterol(LDL-C), high density lipoprotein cholesterol(HDLC), very low density lipoprotein cholesterol(VLDLC). And used ELISA method analyzed TGF-, IL-6, IL-10,IL-17’s levels in serum.3 Experiment 12 weeks end, killed animals with air embolism and extracted carotid tissue, paraffin embedded. The carotid artery stained by HE, observed plaque rupture rates.4 Collected carotid tissue, use reverse transcription polymerase chain reaction(RT-PCR) to detect carotid artery tissue Foxp3, TGF-, IL-10, MMP-2, MMP-9 m RNA expression levels.5 Statistic analysis SPSS 17.0 and Graphpad Prism5 was applied for description and analysis of the data. Measurement data was represented in the form of(mean Std deviation), paired samples t-test was used to compare means of two paired samples. Multiple mernis’ comparison adopted method of One-way ANOVA(Brown-Forsythe method was applied when equal variances not assumed). In cases those equal variances assumed, multiple comparisons of means adopted LSD test(Dunnett’s T3 test was employed when equal variances not assumed).The significance level was 0.05.Results1 The rabbits grew well generally. During the process of the test, the normal control group, model control group no rabbits died, but the model control group can be seen had shed, and skin, toe ulcers. Simvastatin treatment group had two rabbits died of hunger strike. ATRA treatment group had two rabbit died of improper operation gavage. The resulting 30 animal data in the analysis.2 Changes in blood lipid levels: high-fat diet can lead to a significant hyperlipidemia. The model group compared with the control group, TC, LDL-C significantly were increased, simvastatin can effectively reduce TC, LDL-C, ATRA treatment group but no significant improvement of hyperlipidemia.3 Carotid HE staining results Rabbit carotid artery HE staining showed that the control group rabbit carotid artery endothelial cells intact, neat, internal elastic fiber membranes were intact, arterial smooth muscle cells arranged in neat, regular shape, not see obvious plaque formation; model group shows a typical rabbit carotid artery atherosclerotic plaques, there are fibrous cap and lipid core, and inflammatory cell infiltration, internal elastic fiber membrane rupture, arterial intima visible foam cells and cholesterol crystals. Simvastatin group and ATRA treatment group showed endothelial cell morphology is still incomplete, partial disruption of the internal elastic fiber membrane intact clear, visible part of the smooth muscle cells migrate to the next intimal arterial smooth muscle cells arranged in neat yet, the visible part of the formation of foam cells and a small amount of inflammatory cell infiltration.4 ELISA Results: Compared with the model group, simvastatin and ATRA treatment significantly increased the serum anti-inflammatory cytokine TGF- and IL-10 concentration levels and reduces the proinflammatory cytokine IL-6, IL-17 the level of concentration.5 RT-PCR results: real-time quantitative RT-PCR results showed that, compared with the normal control group, model control group rabbit carotid artery tissue TGF- 1, IL-10 and Foxp3 m RNA were significantly reduced, there is a significant difference(P <0.05). Compared with the model group, simvastatin group and ATRA treatment groups anti-inflammatory cytokine TGF- 1, IL-10 and Foxp3 m RNA levels were significantly increased, there was a significant difference(P <0.05), but no difference between the two contrast effect significantly(P> 0.05). Compared with normal control group, model control group rabbit carotid artery tissue MMP-2 and MMP-9 m RNA levels were significantly increased, there was a significant difference(P <0.05). Compared with the model group, simvastatin group and ATRA treatment group MMP-2 and MMP-9 m RNA were significantly reduced, there is a significant difference(P <0.05), but the contrast between the two effects no significant difference(P> 0.05).Conclusion1 Simvastatin can effectively improve hyperlipidemia, and all-trans retinoic acid had no significant effect on blood lipid levels, it is not by lowering lipid levels to reduce atherosclerosis.2 ATRA by TGF- / Smad pathway stimulation Foxp3 expression, promote T cells into regulatory T cells into mature, and the inhibitory effect of T cell activation, downstream anti-inflammatory cytokine TGF- and IL-10 in the level of concentration, proinflammatory cytokine IL-6, IL-17 concentration levels decreased, thereby reducing or inhibiting the local inflammatory response of the body, improve early carotid atherosclerosis.3 ATRA by TGF- / Smad pathway is involved in inflammatory cells inhibit MMP-2, MMP-9 expression, so that the extracellular matrix proliferation, thereby stabilizing vulnerable plaque. |
PDF Full Text Request