有氧运动对胰岛素抵抗小鼠骨骼肌球形脂联素及腺苷酸活化蛋白激酶的影响

The Effect of Adiponectin and AMPK in the Process of Aerobic Exercise Improving Insulin Resistance

目的:通过研究有氧运动对高脂饮食诱导的胰岛素抵抗(IR)小鼠骨骼肌球形脂联素及腺苷酸活化蛋白激酶(AMPK)的影响,试图为运动防治IR提供理论依据。方法:选用雄性C57BL/6小鼠40只,随机分为正常饮食组和IR模型组,正常饮食组以基础饲料喂养8周后再分为正常饮食安静组(NC,n=10)和正常饮食运动组(NE,n=10);IR模型组喂饲高脂饲料8周后再分为高脂安静组(HC,n=10)和高脂运动组(HE,n=10)。NE和HE组进行6周、75%最大摄氧量强度的跑台训练。采用小型血糖仪分别检测口服糖耐量试验后0、15、30、60、90、150、180分钟各时间点的血糖值,并计算血糖曲线下面积(AUC);Northern blot检测AMPK mRNA表达;Western blot和免疫荧光染色检测骨骼肌球形脂联素和AMPK蛋白表达;ELISA法检测空腹胰岛素水平;HE染色观察胰岛细胞形态学变化。结果:HE组小鼠空腹血浆胰岛素水平和AUC均较HC组显著降低。NE组骨骼肌中球形脂联素较NC组显著增加,但HE组无明显变化;无论在正常饮食组还是高脂组,运动均能使AMPK mRNA和蛋白表达显著增高。结论:有氧运动可能通过增加骨骼肌中AMPK蛋白表达,从而促进骨骼肌细胞的糖、脂代谢,达到改善高脂饮食诱发的IR症状的效果。

Objective In order to provide theoretic evidence of exercise-preventing for insulin resistance, we studied the effects of aerobic exercise on expression of adiponectin and AMPK in skeletal muscle of mice with insulin resistant induced by high fat diet. Methods 40 male C57BL/6 mice were randomly divided into control group and IR model group, fed by normal chow and high fat diet respectively. After 8 weeks, the control group were randomly divided into normal chow control group （NC）, and normal chow exercise group （NE） ; IR model group were also randomly divided into high fat diet control group （HC） and high fat diet exercise group （HE）. NE and HE groups were required to running on treadmill for 6 weeks. After 6 weeks, mice were sacrificed and muscles were removed for mRNA and protein analysis. Northern blot was adapted to detect AMPK mRNA expression in skeletal muscle and Western blot to detect globular adiponeetin （G-Adiponectin） and AMPK in skeletal muscle. Fasting insulin concentration was measured by ELISA. The serum glucose concentration was measured by using One Touch meter at the time point of T0,T15, T30, T60, T90, T150 and T180 min respectively, and OGTT glucose area was calculated under the curve （AUC） constituted by the points. HE staining was performed and the morphological changes were evaluated in pancreatic islet cell. Results The serum fasting insulin level and area under the curve of glucose response in HE group was significantly decreased comparing to that of HC group. The skeletal muscle globular adiponectin in NE group were significantly higher than that of NC group after exercise, but the skeletal muscle globular adiponectin in NE group were not changed significantly. Aerobic exercise made AMPK mRNA and protein expression significantly higher both in control diet group and high-fat diet group. Conclusion 6 week of aerobic exercise ameliorates insulin resistance in mice by promoting glucose and lipid metabolism in skeletal muscle evidenced by elevated AMPK protein expression.