目的:研究胰高血糖素样肽-1(GLP-1)受体激动剂Exendin-4对雄性ApoE-/-小鼠髓源性抑制细胞(MDSCs)比例的影响,研究血浆和脾脏组织中炎症因子浓度的变化,并评估其与MDSCs的相关性。
方法:30只雄性ApoE-/-小鼠随机分为5组(每组6只):对照组(CON)。模型组(MOD),Exendin-4干预组(MOD/Ex-4),Exendin-9-39干预组(MOD/Ex-9-39),和Exendin-4+Exendin-9-39联合干预组(MOD/Ex-4+Ex-9-39)。药物干预4周后,使用油红O染色和H&E染色观察主动脉斑块的变化。采用流式细胞术检测骨髓和外周血中髓源性抑制细胞(MDSC)的含量。采用ELISA法检测小鼠外周血血浆中炎症因子的浓度,而RT-qPCR用于定量脾脏中炎症因子的表达水平。采用Pearson相关分析评估MDSCs与炎症因子的关系。
结果:MOD组小鼠的体重明显高于CON组,差异具有统计学意义(P<0.05)。在Exendin-4干预之后,与MOD组相比,体重降低(P<0.05)。此外,与MOD组相比,Exendin-4治疗导致动脉粥样硬化斑块显著减少(P<0.001)。Exendin-4干预后,骨髓中MDSCs的比例高于MOD组(P<0.001),MDSCs在外周血中的比例显著高于MOD组(P<0.05)。进一步的研究表明,Exendin-4可以调节小鼠的血脂水平,降低TG浓度(P<0.01),TC(P<0.0001),和LDL-C(P<0.0001),同时增加HDL-C浓度(P<0.01)。此外,Exendin-4治疗后,外周血细胞因子IL-6水平显著低于MOD组(P<0.0001),而IL-10和TGF-β水平明显高于MOD组(P<0.0001)。在脾脏里,与MOD组相比,细胞因子IL-10(P<0.0001)和TGF-β(P<0.001)的水平显着增加。Pearson相关性分析显示,外周血中MDSCs比例与脾脏和外周血中IL-10、TGF-β水平均呈正相关。此外,骨髓中MDSCs的比例与脾脏和外周血中IL-10和TGF-β水平呈正相关。
结论:Exendin-4可减轻动脉粥样硬化的严重程度。该过程可以通过促进动脉粥样硬化ApoE-/-小鼠骨髓和外周血中骨髓来源的抑制细胞(MDSC)的分泌来实现。调节体内炎症因子的比例,减轻老鼠的体重,降低血脂。
OBJECTIVE: To investigate the impact of the glucagon-like peptide-1 (GLP-1) receptor agonist Exendin-4 on the proportion of myeloid-derived suppressor cells (MDSCs) in male ApoE-/- mice, and investigate alterations in the concentrations of inflammatory factors in plasma and spleen tissues and assess their correlation with MDSCs.
METHODS: Thirty male ApoE-/- mice were randomly divided into five groups (n = 6 per group): control group (CON), model group (MOD), Exendin-4 intervention group (MOD/Ex-4), Exendin-9-39 intervention group (MOD/Ex-9-39), and Exendin-4 + Exendin-9-39 combined intervention group (MOD/Ex-4 + Ex-9-39). After 4 weeks of drug intervention, changes in aortic plaque were observed using Oil Red O staining and H&E staining. Flow cytometry was employed to detect the content of myeloid-derived suppressor cells (MDSCs) in bone marrow and peripheral blood. ELISA was utilized to measure the concentrations of inflammatory factors in mouse peripheral blood plasma, while RT-qPCR was employed to quantify the expression levels of inflammatory factors in the spleen. Pearson correlation analysis was conducted to assess the relationship between MDSCs and inflammatory factors.
RESULTS: Mice in the MOD group had significantly higher body weight compared to the CON group, with a statistically significant difference (P<0.05). Following Exendin-4 intervention, body weight was reduced compared to the MOD group (P<0.05). Additionally, Exendin-4 treatment led to a significant reduction in atherosclerotic plaque compared to the MOD group (P<0.001). After Exendin-4 intervention, the proportion of MDSCs in the bone marrow was higher than in the MOD group (P<0.001), and the proportion of MDSCs in peripheral blood was significantly higher than in the MOD group (P<0.05). Further investigation revealed that Exendin-4 could regulate lipid levels in mice, decreasing concentrations of TG (P<0.01), TC (P<0.0001), and LDL-C (P<0.0001), while increasing HDL-C concentrations (P<0.01). Moreover, after Exendin-4 treatment, the level of the cytokine IL-6 in peripheral plasma was significantly lower compared to the MOD group (P<0.0001), while levels of IL-10 and TGF-β were significantly higher compared to the MOD group (P<0.0001). In the spleen, levels of the cytokines IL-10 (P<0.0001) and TGF-β (P<0.001) were significantly increased compared to the MOD group. Pearson correlation analysis showed that the proportion of MDSCs in peripheral blood was positively correlated with IL-10 and TGF-β levels in both the spleen and peripheral blood. Additionally, the proportion of MDSCs in the bone marrow was positively correlated with IL-10 and TGF-β levels in the spleen and peripheral blood.
CONCLUSIONS: Exendin-4 alleviates the severity of atherosclerosis. This process may be achieved by promoting the secretion of myeloid-derived suppressor cells (MDSCs) in the bone marrow and peripheral blood of atherosclerotic ApoE-/- mice, regulating the ratio of inflammatory factors in the body, reducing mouse body weight, and lowering blood lipids.