节点文献
高原鼢鼠、高原鼠兔的骨骼肌对低氧环境的适应机制
Adaptive Mechanisms of the Hypoxic Environment in Skeletal Muscle of Plateau Zokor (Myospalax Rufescens Baileyi) and Plateau Pika (Ochotona Curzoniac)
【作者】 朱世海；
【导师】 魏登邦；
【作者基本信息】 青海大学 ， 动物营养与饲料科学， 2009， 硕士
【摘要】 高原鼢鼠和高原鼠兔是青藏高原土著动物,对低氧具有很好的适应性。为了探讨高原鼢鼠和高原鼠兔骨骼肌摄氧功能与其生活习性的关系,以SD大鼠为对照,应用免疫组化方法测定了三种动物骨骼肌微血管密度(CD),结果发现,高原鼢鼠骨骼肌细胞中微血管密度显著高于SD大鼠(P<0.05),SD大鼠骨骼肌细胞中微血管密度显著高于高原鼠兔(P<0.05);以显微体视学技术测量了线粒体的数量和面积,结果发现,高原鼢鼠和SD大鼠骨骼肌细胞中线粒体面数密度(NA)和比表面积(δ)无显著差异(P>0.05),但显著高于高原鼠兔(P<0.05)。高原鼠兔、高原鼢鼠和SD大鼠骨骼肌线粒体体密度(VV)及面密度(SV)依次显著增加(P<0.05);用分光光度法测定了三种动物骨骼肌肌红蛋白(Mb)含量、结果显示,高原鼢鼠骨骼肌中肌红蛋白含量为高原鼠兔的两倍多,为SD大鼠的三倍多;乳酸(LD)含量和乳酸脱氢酶(LDH)活力;采用聚丙烯酰胺凝胶电泳(PAGE)观察了三种动物LDH同工酶谱。结果表明:在高原鼠兔和SD大鼠骨骼肌中,LDH活力和LD含量无显著差异(P>0.05);但显著高于高原鼢鼠(P<0.05)。同工酶酶谱显示,高原鼢鼠骨骼肌中M亚基含量相对较低,H亚基含量相对较高,而高原鼠兔和SD大鼠骨骼肌中M亚基含量明显高于H亚基含量,高原鼠兔骨骼肌中毛细血管密度、线粒体数量和面积均显著低于高原鼢鼠和SD大鼠;高原鼢鼠、高原鼠兔和SD大鼠骨骼肌中Mb含量依次降低,并有显著性差异;高原鼢鼠骨骼肌中LDH活力和LD含量显著低于高原鼠兔,高原鼢鼠和SD大鼠没有显著的差异。同工酶酶谱显示,高原鼢鼠骨骼肌中M亚基含量相对较低,H亚基含量相对较高,而高原鼠兔和SD大鼠骨骼肌中M亚基含量明显高于H亚基含量。为探究高原鼢鼠和高原鼠兔对低氧高二氧化碳生境的适应机理分子生物学水平上差异,用real time PCR检测HIF-1α、Mb、VEGF、LDH-A、LDH-B基因在骨骼肌mRNA水平表达的测定,结果显示,高原鼢鼠和高原鼠兔骨骼肌HIF-1α基因mRNA水平的表达无显著差异(P>0.05),两种高原动物的表达水平均高于SD大鼠(P<0.05);高原鼢鼠骨骼肌Mb基因mRNA水平的表达与高原鼠兔差异不显著(P>0.05);高原鼠兔和高原鼢鼠明显高于SD大鼠(P<0.05);高原鼢鼠骨骼肌VEGF165基因mRNA水平的表达与高原鼠兔差异不显著(P>0.05);高原鼠兔和高原鼢鼠明显高于SD大鼠(P<0.05);高原鼢鼠骨骼肌LDH-A基因和LDH-B基因mRNA水平的表达与SD大鼠差异不显著(P>0.05);高原鼢鼠和高原鼠兔明显高于SD大鼠(P<0.05)。上述结果说明,高原鼢鼠尽管生活在严重的低氧环境中,但其骨骼肌通过提高微血管密度、Mb的含量以及线粒体数量和面积增强获氧能力,提高有氧获能水平。与之相反,高原鼠兔骨骼肌主要以糖酵解获能,HIF-1α、Mb、VEGF、LDH-A、LDH-B基因在高原鼢鼠和高原鼠兔的骨骼肌mRNA水平表达的测定明显高于SD大鼠,这与两种动物的生活习性密切相关。
【Abstract】 The Plateau zokor (Myospalax rufescens baileyi) and plateau pika (Ochotona curzniae) are species endemic to the Qinghai-Tibet Plateau.To investigate the relationships between function of getting oxygen in skeletal muscle and living habit of plateau zokor (Myospalax rufescens baileyi) and plateau pika (Ochotona curzoniac), the capillary density (CD) of skeletal muscle of plateau zokor and plateau pika were measured by immunohistochemical staining, the numerical density on area (NA) of mitochondria, and surface density (SV)– external surface area density of mitochondria per unit volume of skeletal muscle fiber were obtained by microscopy and stereology.The results showed that the capillary density (CD), the numerical density and the surface area of mitochondria in skeletal muscle of plateau pika were significantly lower than that of SD rat.The content of myoglobin (Mb) and lactic acid (LD), and the activity of lactate dehydrogenase (LDH) in skeletal muscle were determined by spectro-photometer; and the isozyme zymogram were investigated by polyacrylamide gel electrophoresis. There were significant differences in the content of myoglobin among three species, of which plateau zokor and SD rat presented the highest and the lowest value, respectively. The activity and the content of lactate dehydrogenase in skeletal muscle of plateau zokor were significantly lower than that of plateau pika, and there was no significant difference between plateau zokor and SD. The isozyme zymogram indicated that the content of H subunit was higher than that of M subunit in skeletal muscle of plateau zokor, while in skeletal muscle of plateau zokor and SD, the content of M subunit was high than that of H subunit.To explore the adaptive mechanisms of blood in plateau zokor and plateau pika to the hypoxic environment, the content of HIF-1αmRNA and Mb mRNA and VEGF165 mRNA , LDH mRNA in skeletal muscle were determined by the RT-PCR. The results indicated that,there was no significant difference in the content of HIF-1αmRNA and Mb mRNA and VEGF165 mRNA in skeletal muscle between plateau zokors and plateau pikas, but the content of all in skeletal muscle in the two species were higher than that in SD rats. there was no significant difference in LDH mRNA in skeletal muscle between plateau zokor and SD, the content of LDH mRNA in skeletal muscle of plateau zokors was significantly lower plateau pikas.In conclusion, the results suggest that even though plateau zokor inhabit in the hypoxia environment, they obtains energy with aerobic oxidation by increasing the number and surface area of mitochondria, capillary density and content of myoglobin in the cardiac muscle, while the plateau pika obtain energy through glycolysis, which significantly related to the different living habits of two high altitude species.