胰岛素样生长因子Ⅰ原位注射抑制骨骼肌失神经萎缩

Effect of rhIGF-Ⅰ on the Denervated Skeletal Muscle

目的 :研究胰岛素样生长因子Ⅰ (IGF Ⅰ )原位注射抑制骨骼肌失神经萎缩的可行性 ,为失神经肌萎缩的预防及治疗提供新的手段。方法 :2 4只成年SD大鼠 ,随机分成 2组 ,切断胫神经建立失神经支配的动物模型 ,A组于失神经支配的骨骼肌内注射rhIGF Ⅰ ,用量为 2 5 0ng/kg·2d ,B组注射生理盐水作为对照。 4周后观察比较骨骼肌湿重、骨骼肌细胞横截面积和超微结构。结果 :4周后 ,A组骨骼肌湿重为 (5 0 9.4± 92 .3 )mg、骨骼肌细胞横截面积为 (73 1.0 2±110 .64 ) μm2 ;B组骨骼肌湿重为 (4 61.8± 48.1)mg、骨骼肌细胞横截面积为 (5 77.2 2± 60 .64 ) μm2 。B组骨骼肌萎缩程度明显大于A组。超微结构也提示局部注射rhIGF Ⅰ对失神经支配的骨骼肌细胞的超微结构具有保护作用。结论 :失神经骨骼肌内局部注射rhIGF Ⅰ ,对其萎缩有一定的抑制作用。

Objective:To investigate the influence of insulin like growth factor Ⅰ(IGF-Ⅰ) on the denervated atrophy.Methods:Twenty-four adult Spray-Dawley rats were randomly divided into two groups.The model of denervated gastrocnemius muscls was made by cutting off the tibial nerve.The rhIGF-Ⅰ with 250ng/kg·2d was directly injected into the denervated skeletal muscle of group A and the physiological saline was directly injected into the denervated skeletal muscle of group B as the control group.Four weeks later,the muscle wet weight and the cross section area of myocyte were measured and the ultrastructure of myocyte was observated.Results:The muscle wet weight of group A and group B were (509.4±92.3)mg and (461.8±48.1)mg respectively and the cross section area of myocyte were (731.02±110.64)μm 2 and (577.22±60.64)μm 2 respectively.Skeletal muscle atrophy of group B was more seriously than that of group A.The observation of ultrastructure of myocyte showed that injection of rhIGF-Ⅰ could protect the ultrastructure of myocyte.Conclusion:Direct injection of rhIGF-Ⅰ into the denervated skeletal muscle might inhibit it from atrophy.