【作者】 李庆；

【导师】 汪渊； 魏伟；

【作者基本信息】 安徽医科大学 ， 药理学， 2010， 博士

【摘要】 背景动脉粥样硬化(Atherosclerosis,AS)是心脑血管病的主要病理学基础,是严重危害人类健康的主要疾病,目前机理尚未完全阐明。越来越多的证据表明AS是一种慢性炎性病变,炎症反应是AS的主要发病机制,固有的和获得性的免疫炎症机制参与了此疾病的发展过程。急性冠脉综合征(acute coronary syndrome, ACS)主要包括急性心肌梗死(acute myocardial infarction , AMI)和不稳定性心绞痛(unstable angina, UA),其病理生理基础是冠状动脉粥样硬化斑块在多种因素作用下稳定性被破坏,导致斑块破裂,并继发血栓形成。冠状动脉粥样斑块免疫炎性反应是导致斑块破裂形成ACS的重要机制之一。因此,深入研究AS和ACS发生的免疫机制,寻找新的拮抗AS和ACS的药物具有重要医学意义。CD4~+CD25~+调节性T细胞(CD4~+CD25~+ regulatory T cells, Treg)和辅助性T细胞17(T help cell 17, Th17)是两类不同于Th1和Th2的CD4+T淋巴细胞。Treg细胞可有效控制自身免疫性疾病和维持自身免疫耐受,其数量和功能的改变与肿瘤、感染、自身免疫性疾病等多种疾病密切相关,Thl7细胞是近来发现的一种CD4+T细胞的新亚型,具有很强的促炎症作用,与多种自身免疫病的发生、发展有关。Treg细胞和Thl7细胞之间存在复杂的相互关系,二者在功能上互相拮抗,两者的平衡在组织炎症和自身免疫性疾病的发生发展中具有重要作用。然而,在AS,尤其是ACS形成中的作用,尚未进行深入探讨。氧化低密度脂蛋白(Oxidized low-density lipoprotein , ox-LDL)与动脉粥样硬化的发展密切相关,ox-LDL可通过多种途径损伤血管内皮,促进平滑肌细胞的增殖和泡沫细胞的形成,从而导致脂质条纹和粥样斑块的形成,并可影响斑块的稳定性和导致ACS的发生。然而,ox-LDL是否也通过破坏Th17/Treg平衡而促进AS和ACS形成,目前尚不清楚。全反式维甲酸(all-trans retinoic acid, ATRA)是维生素A的主要衍生物。ATRA作为重要的生物活性物质,具有激素样作用,在体内产生广泛的生物效应。已有文献报道ATRA在Treg和Th17细胞分化中发挥重要作用。本研究首先检测ACS患者外周血Treg和Th17细胞数量、功能和相关细胞因子表达,探讨ACS患者外周Th17/Treg平衡的变化,然后通过细胞实验分析ATRA和ox-LDL对Th17/Treg平衡的影响,并从其对Treg和Th17细胞分化的影响来探讨其机理;同时从细胞凋亡的角度探讨ACS患者Th17/Treg失衡的机制;最后复制早期大鼠AS模型,通过体内实验验证ATRA对Th17/Treg平衡的影响以及在AS发生中的作用,从而为今后预防和控制AS提供新的方法和依据,同时也为今后进一步开发治疗AS的药物提供新的思路。目的明确Th17/Treg平衡在AS中的作用和意义,并分析ATRA和ox-LDL对Th17/Treg平衡的影响和对在AS形成中的作用,探讨Th17/Treg失衡的机制和ATRA影响平衡的机理。方法(1)本实验首先以冠脉造影正常的对照组和AMI、UA、稳定性心绞痛(stable angina, SA)患者为研究对象,采用多色免疫荧光素法标记细胞抗原,包括细胞膜表面和胞核抗原,如:CD4、CD25、CD127、FoxP3、IL-17等,多参数流式细胞术检测各组患者外周血Treg和Th17细胞表达水平;并应用FACS分选CD4~+CD25~+CD127low、CD4+CD25- T细胞,进行混合淋巴细胞培养,比色法测定CD4~+CD25~+CD127low Treg细胞的抑制功能;RT-PCR检测Th17细胞转录因子RORγt和Treg细胞Foxp3表达水平;ELISA法检测人血清细胞因子水平IL-10、IL-17和6 ox-LDL表达情况;分析血清ox-LDL与Treg和Th17细胞水平的相关性,并通过细胞实验检测ox-LDL对Treg和Th17细胞数量和功能的影响。(2)通过细胞实验和凋亡检测进行机制探讨;ATRA和ox-LDL体外干预检测其对各组患者Th17/Treg失衡的作用,并通过细胞因子诱导实验从Treg和Th17细胞分化的角度分析ATRA影响Th17/Treg平衡的机制;通过流式细胞术检测Treg细胞凋亡和Fas/FasL表达,从细胞凋亡的角度分析ACS患者Treg减少和Th17/Treg失衡的可能机理。(3)采用高脂饮食和免疫损伤相结合,复制大鼠早期AS模型,检测各组Treg和Th17细胞表达情况,通过体内实验进一步验证ATRA对Th17/Treg平衡和AS发生的影响。结果(1)ACS患者外周Treg细胞表达率、相关细胞因子IL-10水平和Treg细胞转录因子FoxP3表达显著降低,Treg细胞抑制功能明显减弱;而外周Th17细胞表达率、相关细胞因子IL-17水平和Th17细胞转录因子RORγt表达显著增强。AMI和UA患者Treg/Th17比值显著低于SA患者和对照组(均P < 0.01)。绝大部分对照组正常人CD4~+CD25~+CD127low/Th17比例大于5,SA组患者为2-4,UA患者1-1.5,AMI患者<0.7。AMI和UA患者血清ox-LDL浓度显著高于SA患者和NCA正常人(P < 0.01);此外,血清ox-LDL浓度与Treg细胞表达率呈显著负相关,而与Th17细胞表达率呈显著正相关(P < 0.01)。细胞实验发现,随着ox-LDL浓度的增加和作用时间的延长,Treg细胞表达率降低,而Th17细胞表达率升高;ACS患者对ox-LDL诱导的Treg和Th17细胞变化更为敏感,变化程度显著高于SA患者和对照组。(2)ATRA共同处理组Treg细胞表达水平明显高于ox-LDL处理组(均P < 0.01),Treg细胞抑制功能也明显增强;而Th17细胞表达率显著低于ox-LDL处理组(均P < 0.01);正常人和SA患者PBMCs与ATRA作用48h后,其Treg和Th17细胞表达水平、Treg细胞抑制功能已与细胞对照接近,而UA和AMI患者也有显著恢复。正常人PBMC经TGF-β1和IL-2诱导72h后,Treg细胞表达显著增强;经IL1-β、IL-6和IL-23诱导72h后,Th17细胞表达也明显增强;与细胞因子诱导组比较,ATRA处理组Treg细胞表达水平显著增高,而Th17细胞表达水平明显下降(均P < 0.01);而ox-LDL处理组Treg和Th17细胞表达无明显变化(均P > 0.05)。因此,ATRA可通过作用于Treg和Th17细胞分化,影响Th17/Treg平衡。ACS患者Treg细胞凋亡较NCA对照和SA患者明显增加(P < 0.01),进一步检测发现ACS患者Fas和FasL表达水平均显著增强(均P < 0.05)。(3)动物实验HE染色显示免疫高脂组动脉内膜增生明显,内皮下有大量泡沫细胞沉积,免疫组及ATRA组动脉病变程度比免疫高脂组减轻,正常组及高脂组动脉内膜连续完整。高脂组及免疫高脂组大鼠血清总胆固醇值较正常组、免疫组增加有显著性差异(P < 0.05),而ATRA处理组与各组间差异无统计学意义。免疫组和免疫高脂组Treg细胞表达水平较正常组和高脂组显著降低(P < 0.05, P < 0.01),而Th17细胞表达水平较正常组和高脂组显著升高(P < 0.05);ATRA处理组较免疫高脂组Treg细胞表达明显升高(P < 0.05),而Th17细胞表达明显降低(P < 0.05)。结论(1)采用免疫损伤结合高脂饮食诱导成功建立早期AS大鼠模型。(2)ACS患者和早期AS大鼠模型均存在Treg和Th17细胞平衡失调,Th17/Treg失衡与AS发生发展密切相关,从而为AS和ACS的预防和治疗提供新的靶点;此外,Th17/Treg平衡还可作为ACS早期诊断和动态监测的敏感指标。(3)ox-LDL可直接影响Th17/Treg平衡,使平衡向Th17偏移,进而引起斑块不稳定和ACS的发生,其机制可能并不通过影响Treg和Th17细胞分化完成。(4)细胞实验和动物实验均表明,ATRA可上调Treg表达,同时降低Th17水平,有效改变Th17/Treg失衡状态,从而抑制AS形成;其机制可能是ATRA促进Treg分化和抑制Th17分化。(5)ACS患者Fas和FasL表达上调,可能通过Fas/FasL途径诱导Treg细胞凋亡,从而导致Treg细胞减少和Th17/Treg失衡。第二部分全反式维甲酸在急性冠脉综合征外周Th17/Treg平衡中的作用及其机制目的分析ATRA对Th17/Treg平衡的影响和在AS形成中的作用,探讨Th17/Treg失衡的机制和ATRA影响平衡的机理。方法ATRA和ox-LDL体外干预检测其对各组患者Th17/Treg失衡的作用,并通过细胞因子诱导实验从Treg和Th17细胞分化的角度分析ATRA影响Th17/Treg平衡的机制;通过流式细胞术检测Treg细胞凋亡和Fas/FasL表达,从细胞凋亡的角度分析ACS患者Treg减少和Th17/Treg失衡的可能机理。结果ATRA共同处理组Treg细胞表达率明显高于ox-LDL处理组(均P < 0.01),Treg细胞抑制功能也明显增强;而Th17细胞表达率显著低于ox-LDL处理组(均P < 0.01);正常人和SA患者PBMCs与ATRA作用48h后,其Treg和Th17细胞表达水平、Treg细胞抑制功能已与细胞对照接近,而UA和AMI组也有显著恢复。正常人PBMC经TGF-β1和IL-2诱导72h后,Treg细胞表达率显著升高;经IL1-β、IL-6和IL-23诱导72h后,Th17细胞表达水平也明显增强;ATRA可促进细胞因子对Treg细胞分化作用和抑制细胞因子对Th17分化作用;而ox-LDL对细胞分化影响不大。ACS患者Treg细胞凋亡较NCA对照和SA患者明显增加(P < 0.01),进一步检测发现ACS患者Fas和FasL表达水平均显著增强(均P < 0.05)。结论ATRA可上调Treg表达,同时降低Th17水平,有效改变Th17/Treg失衡状态;其机制可能是ATRA可促进Treg分化和抑制Th17分化。ox-LDL可直接影响Th17/Treg平衡,但其机制可能并不通过影响Treg和Th17细胞分化完成。ACS患者Fas和FasL表达上调,可能通过Fas/FasL途径诱导Treg细胞凋亡,进而导致Treg细胞减少和Th17/Treg失衡。第三部分全反式维甲酸对早期动脉粥样硬化大鼠模型外周Th17/Treg平衡影响的实验研究目的建立早期AS大鼠模型,并探讨其外周Th17/Treg平衡变化及全反式维甲酸对平衡的影响。方法40只8周龄SD大鼠,随机分为正常组、高脂组、免疫组、高脂免疫组以及ATRA处理组,正常组、免疫组给予正常饲料喂养,高脂组、高脂免疫组以及ATRA处理组给予大鼠高脂饲料喂养,免疫组、高脂免疫组以及ATRA治疗组在第四周皮下注射卵清白蛋白(ovalbumin,OVA)予以初始免疫,3周后腹腔注射OVA加强免疫,一周一次连续5周。ATRA处理组同时予以ATRA灌胃,16周后获取血和动脉。检测血清血脂变化,动脉石蜡组织切片用于HE染色以观察动脉病变;流式细胞术检测各组大鼠外周血Treg和Th17细胞表达率。结果成功建立早期AS大鼠模型,动脉HE染色显示免疫高脂组内膜增生,内皮下可见大量泡沫细胞沉积,中膜轻度萎缩,免疫组及ATRA组内膜轻度增生,内皮下可见泡沫细胞沉积与免疫高脂组相比程度较轻。正常组及高脂组动脉完好。高脂组及免疫高脂组血清TC值较正常组、免疫组增加有显著性差异(P < 0.05),而ATRA组高于正常对照和免疫组,低于高脂和高脂免疫组,但无统计学差异。与正常组及高脂组相比,免疫组及免疫高脂组大鼠Treg细胞表达显著降低,而Th17细胞表达明显增高(P < 0.05, P < 0.01),ATRA组Treg细胞水平与免疫高脂组比较显著升高,而Th17细胞水平明显降低(均P < 0.05)。结论免疫损伤结合高脂喂养可形成早期AS大鼠模型,早期AS大鼠模型存在Treg和Th17细胞平衡失调,ATRA可通过影响Th17/Treg平衡抑制AS形成。更多还原

【Abstract】 Background Atherosclerosis (AS) is the major pathologic basis of cardiovascular and cerebrovascular disease, which is threaten serviously to people’s health and life. However, the pathogenesis of AS has not been fully investigated. More evidences incidate that AS is a chronic inflammatory disease, and inflammation is the main pathogenesis of AS. The inherent and acquired immune inflammatory mechanisms involved in the development of AS. Acute coronary syndrome (ACS) including acute myocardial infarction (AMI) and unstable angina (UA), is caused by atherosclerotic plaque instability under a variety of factors, and lead to plaque rupture and secondary thrombosis. The immune inflammatory response is one important mechanism of plaque rupture and the onset of ACS. Accordingly, it has important significance for medical science to lucubrate the immune mechanism of AS and ACS and to look for new medicine to treat AS and ACS.CD4~+CD25~+ regulatory T (Treg) cells and T-helper 17 (Th17) cells are 2 original subsets distinguished from Th1 and Th2 cells. Treg cells can control autoimmune diseases and maintain immune tolerance effectively. The alterations of Treg number and function are closely related to tumor, infection, autoimmune diseases and other diseases. Th17 cells, a new CD4+ T cell subtype, have strong pro-inflammatory effects, and involve in the occurrence and development of many autoimmune diseases. There is complex relationship between Treg and Th17 cells, and the two cells are mutually antagonistic in functions. The balance of Treg and Th17 cells plays important roles in tissue inflammation and autoimmune diseases. However, Th17/Treg balance in AS, especially ACS patients has not been fully investigated.Oxidized low density lipoprotein (ox-LDL) is closely correlated with the development of AS. Ox-LDL can damage endothelial, promote the proliferation of smooth muscle cells, and favor foam cell formation though various ways, which lead to the formation of lipid streaks and atherosclerotic plaque. Ox-LDL may also affect plaque stability and contribute to the occurrence of ACS, but it is unclear whether ox-LDL also affects the occurrence of AS and ACS by disrupting the balance of the peripheral Tregs and Th17 cells.All-trans retinoic acid (ATRA) is the main derivative of vitamin A. As an important bioactive substance, ATRA has hormone-like effect, and produce wide biological effects. It has been reported that ATRA take an important effect on the differentiation of Treg and Th17 cells.In our study, we examined the frequencies of Th17 and Treg cells, key transcription factors and relevant cytokines in patients with AMI, UA, stable angina (SA) and controls, and investigated the alteration of Th17/Treg balance in ACS patients. Then by cellular experiments in vitro, we analyze the effect of ATRA and ox-LDL on the number and function of Treg and Th17, and elucidate the roles of ox-LDL and ATRA in the onset of ACS from the perspective of cell differentiation. We also explored the mechanism of Th17/Treg imbalance in ACS patients from the angel of cellular apoptosis. In addition, we duplicated early AS rat model, and verified the effect of ATRA on Th17/Treg balance and the role in AS. We hope to find new method and basis for prevention and control of ACS, and provide a new approach for development of drugs for AS treatment. Aim To clarify the effect and significance of Th17/Treg balance in AS, to analyze the effect of ATRA and ox-LDL on Th17/Treg balance as well as atherogenesis, and to explore the mechanism of Th17/Treg imbalance and ATRA on the balance.Methods (1)We chose the subjects including AMI, UA, stable angina (SA) and control with normal coronary arteries (NCA). Surface and cytoplasma antigens (such as CD4, CD25, CD127, FoxP3, IL-17 et al.) were detected by Multicolor Immunofluorescence labeling method, and the frequency of Treg and Th17 cells was analyzed by multiparameter flow cytometry. CD4~+CD25~+CD127low and CD4+CD25- cells were sorted by flow cytometry. Treg cells from 4 groups were assayed for their suppressive activity in the allogeneic mixed lymphocyte response (MLR) assay. RORγt and Foxp3 expression levels were detected by RT-PCR. We analyzed the correlations of serum ox-LDL to Th17/Treg frequency, and the effects of ox-LDL on Th17/Treg cells in vitro. The levels of serum Interleukin 10 (IL-10), IL-17 and ox-LDL were measured by ELISA. The effects of ox-LDL on Th17/Treg cells were analyzed in vitro. (2) The mechanisms of Th17/Treg imbalance were explored by experiment in vitro and apoptosis analysis. The effects of ATRA on Th17/Treg imbalance were analyzed by ATRA intervention test in vitro, and it’s mechanism about Treg and Th17 expression was demonstrated by cytokine-induced experiment. Treg apoptosis and expression of Fas, FasL in ACS patients were detected by FCM. (3) A rat model about early AS was established by immune injury and cholesterol diet. Expression of Treg and Th17 was measured by FCM. The effect of ATRA on Th17/Treg balance was further validated in vivo.Results (1) ACS patients have shown a significant decline of Treg frequency, Foxp3 expression, suppressive function, and serum IL-10, and a obvious increase of Th17 frequency, RORγt expression and serum IL-17. The ratio of Treg/Th17 cells was markedly lower in AMI and UA patients than in SA and NCA groups (P < 0.01). The ratio of CD4~+CD25~+CD127low /Th17 cells was mostly > 5 in NCA subjects and 2-4 in SA patients, but 1-1.5 in UA patients and <0.7 in AMI patients. The concentration of ox-LDL increased more significantly in the AMI and UA patients than in SA and NCA groups (P < 0.01). In addition, ox-LDL concentrations in serum were negatively correlated with the frequency of Treg cells (P < 0.01), and positively correlated with the frequency of Th17 cells (P < 0.01). We found that, with increased ox-LDL concentrations and prolonged incubation times, the frequency of Treg cells was decreased while the frequency of Th17 cells was elevated. Treg and Th17 cells from AMI and UA patients were more susceptible to the influence of ox-LDL when compared to those in NCA and SA subjects. (2) Frequency of Treg cells and Treg suppressive function was higher significantly while Frequency of Treg cells was lower obviously in group treated with ox-LDL and ATRA than in group only treated with ox-LDL (all P < 0.01). When PBMCs from NCA and SA groups were co-cultured with ox-LDL and ATRA for 48h, Treg and Th17 expression and Treg function had been close to cellular control. In addition, recovery of Treg and Th17 expression and Treg function were also significant in PBMCs from UA and AMI patients. Induced by TGF-β1 and IL-2 for 72h, expression of Treg cells were increased significantly, while Induced by IL1-β, IL-6 and IL-23 for 72h, expression of Th17 cells were also elevated obviously. Expression of Treg cells in ATRA treatment group was higher significantly than those in cytokine-induced group (P < 0.01), but expression of Th17 cells in ATRA treatment group was lower obviously than those in cytokine-induced group (P < 0.01). There was no difference in expression of Treg and Th17 cells between ox-LDL treatment group and cytokine-induced group (all P> 0.05). Apoptotic Treg cells were higher significantly in AMI and UA groups than in NCA and SA groups(P < 0.01).Compared with NCA and SA groups, Fas and FasL expression in Treg from AMI and UA groups was higher significantly(all P < 0.05). (3) About rat model, the results of HE staining shown that there are edematous thickening of the intima with deposition of a large number of foam cells and a mild atrophy in the membrane in the group treated with cholesterol diet and immune injury, there was a less extent on pathological changes in immune injurey groups and ATRA treatment groups.Total cholesterol (TC) in serum of the cholesterol diet group, the cholesterol diet plus immune injury group increased significantly compared with normal group and immune injurey group (P < 0.05), but the levels of TC did not differ significantly between ATRA treatment group and other groups. Treg expression in immune injurey group and cholesterol diet plus immune injury group was lower significantly while Th17 expression was higher obviously than that in normal and cholesterol diet group (P < 0.05). Treg levels in ATRA treatment group were increased significantly while Th17 levels in ATRA treatment group were decreased significantly than those in cholesterol diet plus immune injury group.Conclusions (1) A early AS rat model was established successfully by immune injury and cholesterol diet. (2) Th17/Treg imbalance exists in ACS patients and early AS rat model. The Th17/Treg imbalance is not only closely related to the onset of ACS, but also possibly used as a sensitive indicator to early diagnosis and dynamic monitoring of ACS. (3) Ox-LDL has a direct effect on Th17/Treg imbalance, and differential sensitivity in ACS patients to ox-LDL results in the aggravation of the Th17/Treg imbalance, which may contribute to plaque destabilization and pathogenesis of ACS. However, this action was not correlated with effect on Treg and Th17 cell induced expression. (4) It is shown in experiment in vitro and rat model that ATRA can up-regulated Treg expression, down-regulated Th17 expression, and altert the state of Th17/Treg imbalance effectively, which can suppress atherogenesis. The possible mechanism is that ATRA could promote Treg cell differentiation and inhibit Th17 differentiation. (5) Expression of Fas and FasL in ACS patients was elevated, and Treg apoptosis was induced by Fas/FasL pathway, which may lead to Treg reduction and Th17/Treg imbalance. The Effect and Mechanism of ATRA on Peripheral Th17/Treg Balance in Patients with Acute Coronary SyndromeAim To analyze the effect of ATRA on Peripheral Th17/Treg balance and atherogenesis, and to explore the mechanism of Th17/Treg imbalance and ATRA on the balance.Methods The effects of ATRA on Th17/Treg imbalance were analyzed by ATRA intervention test in vitro, and it’s mechanism about Treg and Th17 differentiation was demonstrated by cytokine-induced experiment. Treg apoptosis and expression of Fas, FasL in ACS patients were detected by FCM.Results Frequency of Treg cells and Treg suppressive function was higher significantly while Frequency of Treg cells was lower obviously in group treated with ox-LDL and ATRA than in group only treated with ox-LDL (all P < 0.01). When PBMCs from NCA and SA group were co-cultured with ox-LDL and ATRA for 48h, Treg and Th17 expression and Treg function had been close to cellular control. In addition, recovery of Treg and Th17 expression and Treg function were also significant in PBMCs from UA and AMI patients. Induced by TGF-β1 and IL-2 for 72h, expression of Treg cells were increased significantly, while Induced by IL1-β, IL-6 and IL-23 for 72h, expression of Th17 cells were also increased obviously. Expression of Treg cells in ATRA treatment group was higher significantly than those in cytokine-induced group (P < 0.01), but expression of Th17 cells in ATRA treatment group was lower obviously than those in cytokine-induced group (P < 0.01). There was no difference in expression of Treg and Th17 cells between ox-LDL treatment group and cytokine-induced group (all P> 0.05). Apoptotic Treg cells were higher significantly in AMI and UA group than in NCA and SA group(P < 0.01).Compared with NCA and SA group, Fas and FasL expression in Treg from AMI and UA group was also higher significantly(all P< 0.01)Conclusins ATRA can up-regulated Treg expression, down-regulated Th17 expression, and change the state of Th17/Treg imbalance effectively. The possible mechanism is that ATRA could promote Treg cell differentiation and inhibition of Th17 differentiation. Ox-LDL has a direct effect on Th17/Treg imbalance, but this effect was not correlated with Treg and Th17 cell differentiation. Expression of Fas and FasL in ACS patients was elevated, and Treg apoptosis was possibly induced by Fas/FasL pathway, which may lead to Treg reduction and Th17/Treg imbalance. Effects of ATRA on Peripheral Th17/Treg ImBalance in early experimental arteriosclerosis rat modelAim To establish early experimental AS rat model, and to investigate Peripheral Th17/Treg ImBalance and the effects of ATRA on the balance in the model.Methods Fourty 8-week-old Sprague Dawley rats were randomly divided into 5 groups: the normal group (Group 1), cholesterol diet group (Group 2), immune injury group (Group 3), cholesterol diet plus immune injury group (Group 4), and cholesterol diet+ immune injury + ATRA group (Group 5). Rat in Groups 1 and 3 were fed with normal diet, and other group rats fed with cholesterol diet. Rat in all the groups were fed for 16 weeks. Rat in Groups 3 and 4 were immunized with ovalbumin. Rat in Group 5 were immunized with ovalbumin and treated with ATRA.For all the 5 groups, blood and aorta samples were obtained after 16 weeks. TC and TG in serum were measured by ELISA, histological changes in aorta were analyzed by HE staining, and the frequencies of Th17 and Treg cells in peripheral blood were detected by flow cytometry.Results A early AS rat model was established successfully. The results of HE staining shown that there are edematous thickening of the intima with deposition of a large number of foam cells and a mild atrophy in the membrane in Groups 4, there was a less extent on pathological changes in Group 3 and Group 5. TC in serum of Groups 2 and 4 increased significantly compared with Groups 1 and 3 (P <0.05), but the levels of TC in Group 5 have no significant difference compared with those of other groups. Expression of Treg was lower significantly while expression of Th17 was higher obviously in group 3 and group 4 than that in group1 and group 2 (P < 0.05, P < 0.01 respectively). Treg levels in Group 5 were increased significantly while Th17 levels in Group 5 were decreased significantly than those in Group 4. Conclusions A early AS rat model was established successfully by immune injury and cholesterol diet. The shift of the Th17/Treg cell balance from Treg cells towards Th17 cells exists in rat model, and ATRA may play an important role in inhibiting AS development by affecting the peripheral Th17/Treg balance.更多还原