雌、雄草原田鼠外周骨骼肌肌球蛋白重链的表达(英文)

Myosin heavy chain expression in peripheral muscles of male and female prairie voles Microtus ochrogaster

已往的研究对于实验室应用的各种啮齿类动物,如大鼠和小鼠骨骼肌蛋白表达的特性已有报道。然而,至今不清楚其它啮齿类动物如野生鼠骨骼肌蛋白的表达或性双态性的特征,而这些野生鼠的行为学、形态学及生理学特点均已有报道。已知骨骼肌的肌球蛋白重链( MHC)成分与其功能特性有关。我们研究了草原田鼠的肱三头肌、胫骨前肌、腓肠肌和比目鱼肌MHC蛋白表达的性别特性。应用SDS聚丙烯酰胺凝胶电泳法测定MHCⅠ型、Ⅱa型、Ⅱd/x和Ⅱb型的蛋白表达相对含量。结果表明:与雌鼠相比,雄鼠的比目鱼肌湿重较大,胫骨前肌的MHCⅡa蛋白量表达较高。未见骨骼肌重量及MHC蛋白表达含量在雌雄鼠间的性别差异。血中睾酮的浓度差异可能不影响外周骨骼肌蛋白的表达特性。然而,与过去在大鼠、兔和小鼠中的已报道的结果相比,草原田鼠骨骼肌MHC的表达显示了更多异质性。推测这可能与草原田鼠和其它小型哺乳类动物生存的自然环境和功能需要有关。

Previous research has reported skeletal muscle protein expression characteristics for laboratory strains of various rodents, such as rats and mice. However, we do not know the muscle protein expression or sexual dimorphism characteristics of skeletal muscle for other rodents such as voles, for which the behavior, morphology, and physiology have been documented. Myosin heavy chain （MHC） content in skeletal muscle is related to functional characteristics. This study investigated sex characteristics （male, n = 6 ; female, n = 8） for MHC expression for triceps brachii, tibialis anterior, gastrecnemius, and soleus muscles in prairie voles. Relative （ % ） MHC protein expression was determined via SDS-PAGE for types Ⅰ , Ⅱ a, Ⅱ d/x, and Ⅱ b MHC isoforms. Male voles had greater soleus wet weight and greater Ⅱ a MHC expression for tibialis anterior as compared to those of female voles. Skeletal muscle mass and MHC protein expression were not sexually dimorphic. Differences in circulating testosterone titers did not appear to influence these characteristics of mature peripheral skeletal muscle. Prairie voles, however, exhibited much more heterogeneity in MHC expression as compared to previous reports on rats, rabbits, and mice. It is likely that this is due to differences in the natural history and functional requirements of voles and other small mammals