运动和魔芋多糖对改善2型糖尿病大鼠糖脂异常及骨代谢的机制研究

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摘    要：探討运动和魔芋多糖对2型糖尿病（T2DM）大鼠血糖、血脂、血清骨代谢标志物、骨细胞形态结构及骨代谢蛋白相关表达的影响。方法：将SPF级雄性SD大鼠分为普通安静对照组（NC）、2型糖尿病模型组（DM）、2型糖尿病运动组（DE）、2型糖尿病魔芋多糖组（DK）和运动联合，魔芋多糖干预组（EK），共5组。运动组每次运动时间60 min，每周运动5 d，共计8周。魔芋多糖饲料喂养组，共计8周。干预8周后测试血糖、血脂指标、血清胰岛素、胰岛素样因子-1（IGF-1）、血清骨代谢标志物及骨密度;通过电镜观察成骨细胞和破骨细胞形态和结构;采用Western-blot方法检测骨骼肌中骨代谢相关蛋白IRS-1和IRS-2蛋白表达。结果：与DM相比，所有干预组2型糖尿病大鼠血清TG、TC、FFA含量均降低且血清骨钙素和瘦素水平增加，联合干预组BMD含量增加;与DM相比，上调IRS-2蛋白表达，下调IRS-1蛋白表达，增加钙质的沉积。综合各指标发现，DE较DK效果好，而EK则优于其他各组。结论：1）运动和魔芋多糖单独或联合干预均可降低血糖、血脂，提高血清骨钙素和瘦素水平，其中仅有联合干预组BMD含量提高。2）通过运动和魔芋多糖干预，电镜观察骨细胞凋亡数目一定程度上减少，其中联合干预组效果最好。3）运动和魔芋多糖一定程度上调节血清骨形成的标志物水平，其机制可能是运动和魔芋多糖通过上调IRS-2蛋白表达，下调IRS-1蛋白表达，提高胰岛素的敏感性，降低血糖，促进细胞对钙的摄取，提高骨钙素水平和增加钙质的沉积，从而在一定程度上提高2型糖尿病大鼠的骨密度。

关键词：运动;魔芋多糖;2型糖尿病;骨代谢

中图分类号：G 804.7          学科代码：040302           文献标识码：A

Abstract：Objective： To study the effects of exercise and konjac polysaccharide on blood glucose，  and blood lipid metabolism， serum bone metabolism markers， bone cell morphology and related the bone metabolism protein expression in type 2 diabetes（T2DM） rats. Methods： SPF male Sprague Dawley rats were divided into normal control group （NC）， type 2 diabetes control group （DM）， type 2 diabetes with exercise group（DE）， type 2 diabetes with konjac polysaccharide group （DK）， type 2 diabetes with konjac polysaccharide and exercise intervention group（EK）. 60 min per day and 5 days per week for 8 weeks in exercise groups. Konjac polysaccharide groups feed for 8 weeks. Blood glucose， serum insulin， insulin-like growth factor-1， serum lipids， bone metabolic markers and bone mineral density were measured after 8 weeks’intervention. Osteoblasts and osteoclasts were observed by a transmission electron microscope. The protein expression of IRS-1 and IRS-2 in skeletal muscle was detected by Western-blot. Results： Compared with the DM group， TG， TC， FFA levels and the protein expression of IRS-1 were reduced and serum osteocalcin， leptin levels and the protein expression of IRS-2 were increased in the other groups， while the content of BMD was increased in the EK group; compared with DM，  the expression of IRS-2 protein was increased， IRS-1 protein decreased， and calcium deposition increased， and the index of the DE group is better than the DK group， while that of EK group was superior to other groups. Conclusions： 1） Exercise and konjac alone or in combination group could reduce blood glucose and blood lipids and serum osteocalcin and leptin levels were increased，  and the contents of BMD were increased only in the EK group. 2）In DK， DE and EK groups the apoptosis of bone cell was reduced. Moreover， the EK group had the best effect. 3）The possible mechanism of bone metabolism was improved by exercise or konjac which due to the increasing the protein expression of IRS-2， and decreasing IRS-1， increasing insulin sensitivity， and decreasing blood glucose levels， so as to promote the uptake of calcium by cells， then increase BGP， calcium deposition， and increase bone mineral density in type 2 diabetic rats.