生长分化因子15与胶质源性神经营养因子样受体通路对小鼠动脉粥样硬化进展的影响

Effect of GDF-15/GFRAL pathway on progression of atherosclerosis in mice

目的 探讨生长分化因子15(growth differentiation factor 15,GDF-15)/胶质源性神经营养因子样受体(glial-derived neurotrophic factor receptor alpha-like, GFRAL)通路对载脂蛋白E^(-/-)小鼠动脉粥样硬化进展的影响及可能机制。方法 选择8周龄C57BL/6雄性载脂蛋白E^(-/-)小鼠8只,随机分为对照组和重组GDF-15组,每组4只。对照组:高脂饮食4周后,每周1次尾静脉注射磷酸盐缓冲液;重组GDF-15组:高脂饮食4周后,每周1次尾静脉注射重组GDF-15(0.05 mg/kg)。高脂饮食12周,监测小鼠体质量,处死小鼠。取4只同等周龄(20周龄)正常小鼠作为正常组,比较3组空腹血糖、血脂、皮质醇和醛固酮水平。主动脉冷冻切片油红O染色评估对照组和重组GDF-15组斑块大小。免疫组织化学检测对照组和重组GDF-15组脑组织GDF-15及GFRAL表达。结果 重组GDF-15组血清GDF-15水平较对照组明显升高,差异有统计学意义[(52.59±2.90)ng/ml vs(20.09±1.27)ng/ml,P<0.01]。重组GDF-15组11周和12周体质量较对照组明显减低[(28.60±0.22)g vs(29.47±0.25)g;(28.98±0.22)g vs(30.35±0.13)g,P<0.01]。重组GDF-15组三酰甘油水平较对照组明显降低[(0.22±0.02)mmol/L vs(0.38±0.09)mmol/L,P<0.05]。重组GDF-15组斑块面积明显小于对照组,差异有统计学意义[(22.22±2.58)%vs(31.61±3.51)%,P<0.01]。重组GDF-15组脑组织GDF-15和GFRAL表达较对照组明显增加(0.088±0.007 vs 0.030±0.006,0.031±0.003 vs 0.010±0.001,P<0.01)。对照组及重组GDF-15组皮质醇和醛固酮水平较正常组明显升高,差异有统计学意义(P<0.01)。重组GDF-15组醛固酮水平较对照组明显降低,差异有统计学意义[(22.01±3.67)mg/ml vs(87.29±8.63)mg/ml,P<0.01]。结论 GDF-15可能通过GFRAL调控小鼠体质量、三酰甘油及醛固酮水平影响动脉粥样硬化进展。

Objective To investigate the effects and possible mechanisms of the growth differentiation factor 15(GDF-15)/glial-derived neurotrophic factor receptor alpha-like(GFRAL) pathway on the progression of atherosclerosis in ApoE^(-/-) mice.Methods Eight 8-week-old male ApoE^(-/-) mice were randomly divided into control group and rGDF-15 group.The mice in the control group received an injection of phosphate-buffered saline via tail vein once a week after 4 weeks of high-fat diet feeding, and those in the rGDF-15 group received an injection of recombinant GDF-15(0.05 mg/kg) via tail vein once a week after 4 weeks of high-fat diet feeding.The mice were fed with high-fat diet for another 8 weeks, the body weight was monitored during this period.After 12 weeks' feeding, the mice were euthanized.Another 4 normal mice(at the same age, 20 weeks old) were subjected and served as normal control group.The levels of fasting blood glucose, blood lipids, cortisol, and aldosterone were compared among the three groups.Oil red O staining was used to evaluate plaque size in the aorta, and immunohistochemistry was employed to assess the expression of GDF-15 and GFRAL in the brain tissue.Results The serum level of GDF-15 was higher in the rGDF-15 group than in the control group(52.59±2.90 ng/ml vs 20.09±1.27 ng/ml, P<0.01).The weight of mice was significantly lower in the rGDF-15 group than the control group during Week 11(28.60±0.22 g vs 29.47±0.25 g, P<0.01) and 12(28.98±0.22 g vs 30.35±0.13 g, P<0.01).The rGDF-15 group had a statistically lower level of triglycerides(0.22±0.02 mmol/L vs 0.38±0.09 mmol/L,P<0.05),lighter plaque burden [(22.22±2.58)% vs(31.61±3.51)%,P<0.01],and enhanced expression levels of GDF-15 and GFRAL in the brain tissue(0.088±0.007 vs 0.030±0.006,0.031±0.003 vs 0.010±0.001,P<0.01).The levels of cortisol and aldosterone in the control group and rGDF-15 group were significantly higher than those in the normal group(P<0.01).The aldosterone level in the rGDF-15 group was significantly reduced compared to the control group(22.01±3.67 mg/ml vs 87.29±8.63 mg/ml, P<0.01).Conclusion GDF-15 may regulate body weight and triglyceride and aldosterone levels through GFRAL,and then affect the progression of atherosclerosis.