脂联素及其受体在吡格列酮抑制ApoE基因敲除小鼠主动脉粥样硬化中的作用

Role of adiponectin and its receptors in anti-atherosclerotic effects of pioglitazone on ApoE knocked out mice

目的:观察吡格列酮对ApoE基因敲除小鼠(ApoE-/-小鼠)主动脉粥样硬化病变的影响,并初步探讨血清脂联素及其受体在其中的作用。方法:ApoE-/-小鼠动脉粥样硬化模型组:随机分成3个亚组,安慰剂组(n=10)、小剂量吡格列酮治疗组[10mg/(kg.d),n=10]、大剂量吡格列酮治疗组[20mg/(kg.d),n=10]。以野生型C57BL/6J小鼠(n=9)为对照组。观察ApoE-/-小鼠主动脉病理学改变、腹主动脉超声改变及血清脂联素水平、主动脉脂联素受体R1(adiponectin receptor1,AdipoR1)及脂联素受体R2(adiponectin receptor2,AdipoR2)mRNA表达水平。结果:与野生型C57BL/6J小鼠相比,ApoE-/-小鼠有较明显的主动脉内膜增厚及粥样斑块的形成,而经吡格列酮治疗后病变减轻。ApoE-/-小鼠安慰剂组腹主动脉平均内膜中层厚度(intima-media thickness,IMT)较野生型C57BL/6J小鼠明显增加[(0.290±0.063vs0.178±0.012)cm,P<0.01],而经大剂量吡格列酮治疗后IMT显著减轻[(0.208±0.012vs0.290±0.063)cm,P<0.05]。ApoE-/-小鼠安慰剂组血清脂联素水平低于野生型C57BL/6J小鼠[(12.41±3.84vs18.96±4.89)μg/L,P<0.05],而经低剂量及高剂量吡格列酮治疗后,与安慰剂组比较,均可增加血清脂联素水平(18.78±7.24μg/Lvs12.41±3.84μg/L,P<0.05;24.00±4.71μg/Lvs12.41±3.84μg/L,P<0.05)。ApoE-/-小鼠安慰剂组主动脉脂联素受体AdipoR1mRNA的表达低于野生型C57BL/6J小鼠(0.789±0.167vs0.950±0.071,P<0.05),并且AdipoR1/AdipoR2比值显著下降(1.039±0.062vs0.940±0.102,P<0.05),而经吡格列酮治疗可轻度上调AdipoR1和AdipoR2型受体mRNA的表达,大剂量吡格列酮治疗可显著增加AdipoR1/AdipoR2比值(1.063±0.051vs0.940±0.102,P<0.01)。结论:吡格列酮可抑制动脉粥样硬化的形成,其作用机制可能与提高血清脂联素水平和上调主动脉脂联素受体(尤其是AdipoR1型)表达有关。

Objective ：To study the effects of pioglitazone on atherosclerosis on ApoE-/- mice, and to investigate the roles of adiponectin and its receptors. Methods： ApoE-/- mice were fed with high-fat chow for the induction of atherosclerosis and were divided into three subgroups： placebo（ n = 10） , lowdose[ 10 mg/（ kg· d）,n = 10] pioglitazone therapy, and high-dose[20 mg/（kg·d） ,n = 10] pioglitazone therapy. C57BL/6J wild type mice （n = 9） were used as control. Aortic atherosclerosis and intimamedia thickness （ intima-media thickness , IMT） of abdominal aorta were monitored, and plasma adiponectin was also measured. Expression levels of the adiponectin receptor 1 （AdipoR1）and adiponectin receptor 2 （AdipoR2） in vessels were analyzed（RT-PCR）. Results： （ 1 ） Aortic atheroselerotic lesions were observed in ApoE -/- mice but not in wild type mice. Interestingly, these lesions were significantly prevented by high-dose pioglitazone therapy . Compared with wild type mice , ApoE -/- mice had increased IMT of abdominal aorta [ （0. 290 ±0. 063 vs 0. 178 ±0. 012） cm,P 〈0. 01 ] that was significantly reversed by high-dose pioglitazone therapy[ （0. 208 ±0. 012 vs 0. 290 ±0. 063） cm,P 〈0. 05]. （2） The level of plasma adiponectin was significantly lower in ApoE -/- mice [ （ 12.41 ± 3.84 vs 18.96 ±4.89） μg/L,P 〈 0. 05）, which could be increased by low-and high-dose pioglitazone therapy （18.78 ± 7.24 μg/Lvs 12.41 ±3.84 μg/L,P 〈0.05; and 24.00 ±4.71 μg/L vs 12.41 ±3.84 μg/L,P 〈0.05）. （3） Compared with wild type mice, ApoE -/- mice had reduced AdipoR1 mRNA level（0. 789 ± 0. 167 vs 0. 950 ± 0. 071, P 〈 0.05 ） and reduced the ratio of AdipoR1/AdipoR2 （0. 940 ± 0. 102 vs 1. 039 ± 0. 062, P 〈 0.05 ） ; high dose pioglitazone therapy could upregulate AdipoR1 , AdipoR2 mRNA expression and increase the ratio of AdipoR1/AdipoR2 （ 1. 063 ±0. 051 vs 0. 940 ±0. 102 ,P 〈0. 01 ）. Conclusion： Pioglitazone inhibits aortic atherosclerosis in ApoE-/- mice, and these effects are correlated with increased plasma adiponeetin level and the expression of AdipoR1 mRNA in vessels.