实验大鼠斜方肌肌纤维型组成及分布研究

目的探讨大鼠斜方肌的肌纤维型组成和分布,借以了解该肌功能。方法取成年SD大鼠斜方肌升部肌组织进行冰冻切片(8μm厚),采用Guth-Samaha肌球蛋白ATP酶组织化学染色法并稍做改良,对其进行肌纤维分型研究。结果SD大鼠斜方肌经肌球蛋白ATP酶组织化学染色后可明确分出2种肌纤维型,即白色的Ⅰ型纤维(慢缩纤维)和深褐色的Ⅱ型纤维(快缩纤维),2种肌纤维在肌内呈棋盘样均匀分布;图像分析计数其Ⅰ型纤维占(48.8±6.9)%,Ⅱ型纤维比例为(51.2±6.9)%,2者比较差异无统计学意义(P>0.05)。结论SD大鼠斜方肌2型肌纤维所占比例均等,与其维持颈背部姿势的作用一致。     

大鼠腹外斜肌肌纤维型组成及分布研究

目的探讨大鼠腹外斜肌的肌纤维型组成和分布,借以了解该肌功能,并为运动训练模型的建立提供理论依据和研究平台。方法采用Guth-Samaha肌球蛋白ATP酶组织化学染色法并稍做改良,对成年SD大鼠腹外斜肌冰冻切片进行肌纤维分型研究。结果SD大鼠腹外斜肌经肌球蛋白ATP酶组织化学染色后可明确分出2型肌纤维,即明亮色白的Ⅰ型纤维(慢缩纤维)和幽暗深褐的Ⅱ型纤维(快缩纤维),并且,2种纤维在肌内呈棋盘样均匀分布;图像分析仪下计数Ⅱ型纤维达到(84.8±5.3)%,而Ⅰ纤维仅占(15.2±2.1)%,前者占绝对优势(P<0.01)。结论SD大鼠腹外斜肌以Ⅱ型纤维为主,除了起保护腹腔脏器作用外,还参与力量和速度运动。     

大鼠胸浅肌肌纤维型组成及其葡萄糖转运蛋白4表达特征

目的:研究大鼠胸浅肌不同肌纤维型的组成分布及其葡萄糖转运蛋白4(GLUT4)表达差异,了解该肌功能。方法:采用Guth-Samaha肌球蛋白ATP酶染色法并稍做改良,对成年SD大鼠胸浅肌冰冻切片进行肌纤维分型研究,并用免疫组织化学法对肌纤维分型后的切片进行GLUT4表达分析。结果:大鼠胸浅肌经肌球蛋白ATP酶染色后可明确分出明亮色白的Ⅰ型纤维和幽暗深褐的Ⅱ型纤维,2种纤维在肌内呈棋盘样均匀分布;Ⅰ型纤维比例为(52·6±6·3)%,Ⅱ纤维为(48·4±5·7)%,两者比例均等。免疫组织化学显色结果显示,GLUT4主要存在于包裹肌束的肌膜和Ⅰ型纤维膜上,而Ⅱ型纤维膜表达不明显。结论:大鼠胸浅肌两型纤维比例均等,属耐力兼速度型肌;Ⅰ型纤维膜的GLUT4表达高于Ⅱ型纤维,表明前者葡萄糖摄取能力高于后者。     

大鼠骨骼肌纤维组织化学分型与肌球蛋白重链的功能

目的 研究分析了成年SD大鼠外侧腓肠肌各肌亚体内肌纤维的分布与肌球蛋白重链异构体(MHCs)的构成.方法 应用琥珀酸脱氢酶(SDH)组织化学染色分析其4型肌纤维构成比例与横切面积,并以十二烷基硫酸钠-聚丙烯酰胺小孔梯度凝胶电泳(SDS-PAGE)检测肌球蛋白重链异构体.结果 Ⅰ型慢缩氧化(SO型)肌纤维、ⅡX型快缩氧化(FO型)肌纤维、ⅡA型快缩氧化酵解(FOG型)肌纤维及ⅡB型快缩酵解(FG型)肌纤维的构成比例在内侧亚体分别为(10.2±4.1)%、(2.8±2.1)%、(25.7±9.6)%、(61.3±10.1)%;在外侧浅亚体分别为(15.9±8.2)%、(6.1±2.6)%、(22.8±11.5)%、(55.2±12.6)%;而在外侧深亚体则分别为(21.3±9.2)%、(9.8±2.5)%、(18.5±8.7)%、(50.4±10.9)%.4型肌纤维均呈交错式镶嵌型分布.Ⅰ型肌纤维横切面积较小,ⅡX型肌纤维横切面积最小,ⅡA型肌纤维横切面积中等,ⅡB型肌纤维横切面积最大.与使用SDS-PAGE在内侧亚体、外侧浅亚体及外侧深亚体分别发现的肌球蛋白重链异构体(MHCs)所确定的MHCsⅠ、MHCsⅡx(或Ⅱd)、MHCsⅡa、MHCsⅡb相对应.结论 大鼠外侧腓肠肌的重要功能是屈膝关节和伸跗关节,在提踵推进躯体向前和需少量肌力活动时,主要依靠外侧浅、深亚体的肌纤维完成.只有快速运动使肌力需要25%以上时,才有内侧亚体的参与.     

羊髋部和大腿肌组织的肌纤维类型分布

<正> 组成肌肉内肌纤维类型与其运动和姿势的功能有关。作者在本文检测了组成羊的髋部和大腿肌肉的肌纤维类型和不同的分布。分别以肌球蛋白ATP酶和NADH四唑鎓还原酶(NADH——TR)活动把肌纤维分为Ⅰ型,ⅡA和ⅡB型。股中间肌只由Ⅰ型肌纤维组成,这些纤维显示出弱硷稳定肌球蛋白ATP酶和强NADH——TR活性。臀辅     

背阔肌的组织化学特征研究

本文用酸碱预孵育肌球蛋白ATP酶法、乳酸脱氢酶法、油红O法、PAS法,研究了20只犬的背阔肌.结果表明,用肌球蛋白ATP酶法可将肌纤维分为Ⅰ型和Ⅱ型.Ⅰ型可分为3个亚型,Ⅱ型可分为ⅡA、ⅡB和ⅡC3个亚型.Ⅱ型肌纤维在背阔肌中占的比例大.Ⅱ型肌纤维含有较多糖原,Ⅰ型肌纤维含有较多脂肪颗粒.通过酶的染色观察,Ⅰ型、ⅡB和ⅡC亚型肌纤维的乳酸脱氢酶活性强弱无明显差别,ⅡA亚型肌纤维乳酸脱氢酶活性较弱.本文对背阔肌组织化学特征进行了讨论.     

牵张延长下颌骨对二腹肌纤维型构成影响的研究

目的 :研究牵张延长下颌骨前后二腹肌的组织化学特征。方法 :应用肌球蛋白ATP酶 (pH9.4)染色法 ,观测了牵张前后 8只狗的二腹肌肌纤维类型 ,并用VIDAS图像分析仪测量其横截面积。结果 :ATP酶染色 ,二腹肌肌纤维分为Ⅰ型和Ⅱ型 ,Ⅰ型纤维数量较Ⅱ型纤维少。牵张延长下颌骨后 ,Ⅰ型纤维数量显著性增多 ,Ⅱ型纤维数量显著性减少。牵张成骨后 ,Ⅰ型纤维、、Ⅱ型纤维的横截面积与术前比较没有显著性差异。结论 :牵张延长下颌骨后 ,与牵张方向平行的二腹肌肌纤维型分布发生了与功能变化相适应的改变     

人指屈肌和指伸肌的肌纤维型构成及年龄差异

用尸检取材(死后24小时内),肌球蛋白ATP酶染色法,检测了不同年龄组(共18例,3～69岁)指浅屈肌、指深屈肌和指伸肌的肌纤维型构成.结果表明:中青年组各肌的Ⅰ型纤维比例分别为指浅屈肌47.2%,指深屈肌44.7%,指伸肌47.7%,各肌之间无明显差异.肌纤维型构成随年龄增加而明显变化,各肌Ⅰ型纤维比例均表现为少儿组较高,中青年组较低,而老年组又明显增高,三组之间具有显著差异.文中还讨论了肌纤维型构成与年龄的关系.     

慢性低氧大鼠膈肌纤维横截面积变化

本文通过建立慢性常压和减压低氧大鼠模型 ,采用肌球蛋白ATP酶 (mATP酶 )组化方法将肌纤维分为Ⅰ、ⅡA和ⅡB三种类型和显示毛细血管 ,用计算机图象分析系统测定肌纤维横截面积 (CSA)和毛细血管密度变化 ,观测慢性低氧大鼠膈肌不同类型纤维CSA变化 ,探讨其与毛细血管密度变化的关系。慢性低氧大鼠肌纤维CSA均不同程度缩小 ,CSA缩小与毛细血管密度增加显著相关。膈肌CSA缩小使毛细血管相对密度增加 ,有利于氧运输和弥散 ,膈肌氧化能力增强。     

人三角肌亚部化,肌纤维型分布及面积的研究

根据人三角肌的肌纤维起止、排列和神经支配特征,将该肌分为前、中、后3个亚部。用新鲜男性尸体标本16侧三角肌,按上述3个亚部的浅、深区分别取材,作恒冷箱冰冻横向切片,肌球蛋白ATP酶染色,将肌纤维分为Ⅰ型和Ⅱ型。检测各区的肌纤维型构成比例,并用图像分析仪测量各区两型肌纤维的横切面积和直径。结果发现,肌中部的I型纤维比例明显高于前、后两部,各亚部深区的I型纤维比例均比浅区高,而左、右侧之间无差异。各亚部及浅、深区。Ⅰ、Ⅱ型肌纤维的直径都相似(57～6lμm),仅中部深区Ⅱ型纤维直径(52.9μm)较其他各区肌纤维明显细小;除中部深区外,右侧两型纤维的直径均比左侧稍大,但统计学分析左右侧差异不显著。作者认为,三角肌纤维型分布的肌内差异,与该肌功能的分化密切相关。中部深区的Ⅰ型纤维比例较高,Ⅱ型纤维直径较细,可能提示该区的主要功能是维持肩关节稳定。     

Composition of Muscle Fiber Types in Rat Rotator Cuff Muscles

The rat is a suitable model to study human rotator cuff pathology owing to the similarities in morphological anatomy structure. However, few studies have reported the composition muscle fiber types of rotator cuff muscles in the rat. In this study, the myosin heavy chain (MyHC) isoforms were stained by immunofluorescence to show the muscle fiber types composition and distribution in rotator cuff muscles of the rat. It was found that rotator cuff muscles in the rat were of mixed fiber type composition. The majority of rotator cuff fibers labeled positively for MyHCII. Moreover, the rat rotator cuff muscles contained hybrid fibers. So, compared with human rotator cuff muscles composed partly of slow‐twitch fibers, the majority of fast‐twitch fibers in rat rotator cuff muscles should be considered when the rat model study focus on the pathological process of rotator cuff muscles after injury. Gaining greater insight into muscle fiber types in rotator cuff muscles of the rat may contribute to elucidate the mechanism of pathological change in rotator cuff muscles‐related diseases. Anat Rec, 299:1397–1401, 2016. © 2016 Wiley Periodicals, Inc.     

Histochemical and morphometric studies of the musculature of the forelimb of sheep with reference to its function. 2. Flexor and extensor of carpal and toe joints]

Muscle tissue was obtained from eight forearm muscles of six male sheep (180 days old) and stained for NADH tetrazolium oxidoreductase and myofibrillar ATPase after preincubation at pH 4.3. The fiber diameter and the percentage were determined of three fiber types: slow twitch oxidative (STO), fast twitch oxidative (FTO) and fast twitch glycolytic fibers (FTG). The extensor carpi radialis muscle had the lowest percentage of STO fibers. It is a fast extensor of the carpal joint. The superficial digital flexor muscle (FS) is located in the superficial region of the forearm has shown the highest percentage of STO fibers (50%). These fibers were also considerable larger (57 microns) than the STO fibers of the deep digital flexor muscle (39 microns). The FS supports the elbow joint extensors in the fixation of the elbow joint during the standing position (static work) and flexes the digital joints in motion (dynamic work). At first muscle function decides the quality and the quantity of the muscle fibers. Then other factors, e.g. capillarization, determine the distribution of fiber types. Muscles which have to work static-tonically require a higher content of large slow twitch fibers regardless of whether these muscles are located close to the limb axis or in the periphery. They resist lastingly gravity. Thus they are antigravity muscles. In the forearm they are the superficial digital flexor muscle, flexor carpi ulnaris muscle, and extensor carpi ulnaris muscle, which always have more than 30% STO-fibers.     

Two-dimensional changes of muscle fiber types in growing rat hind limb

In the present study, we examined the changes in two-dimensional distribution of fiber types in the whole area of the rat skeletal muscle and the effect of growth on this distribution. Muscles of rats aged 3 (body weight 58 g), 4 (89 g), 8 (276 g), 12 (312 g), 18 weeks (368 g), and 6 months (450 g) were stained for myofibrillar adenosine triphosphatase (mATPase) with preincubation at pH 4.35. Muscle fibers were classified into type I (slow oxidative), IIA (fast oxidative), IIB (fast glycolytic), and IIX (fast oxidative glycolytic). The x-y coordinates of each fiber were used to analyze the growth-related changes using an image analyzing system. In the tibialis anterior (TA) muscle, type I fibers were predominant in the deep and middle regions at 3 to 4 weeks of age, but became restricted to the deeper region with growth. In the extensor digitorum longus (EDL) muscle, type I fibers were predominant in the deep region at 3 to 8 weeks of age, but decreased gradually with growth and completely disappeared at 6 months of age. Compared with the TA and EDL, type I fibers of the soleus (SOL) muscle were spread throughout the muscle and the number of these fibers tended to increase with growth. Type IIA and IIX fibers of the SOL decreased in number and became restricted to the superficial region with growth. No type IIB fibers were detected in the SOL throughout life. Our results indicated that the growing process influences the distribution, proportion and characteristics of individual muscle fiber types in the rat hind limb muscles.     

Immunohistochemistry of kangaroo rat hindlimb muscles

Kangaroo rats (Dipodomys spp.) use specialized bipedal hopping like that of kangaroos. In contrast to kangaroos that have elastic tendons capable of storing energy, kangaroo rats have inelastic tendons that are unable to store large amounts of energy. Thus, the musculature of the ankle joint provides the greatest power contribution to kangaroo rat hopping. Skeletal muscle can be characterized by several fiber types, including slow twitch (Type I) and fast twitch (Type II) fibers. Fast fibers are found in higher concentration in muscles that perform quick, dynamic movements, whereas slow fibers are found in higher proportion in muscles that perform slow, endurant movements. Using fiber type specific antibodies, we identified four pure (Types I, IIA, IIB, and IIX) and two hybrid (Types I/IIA and IIA/IIX) fiber types in six hindlimb muscles from three kangaroo rats (Dipodomys merriami) to investigate the relationship between fiber composition and hindlimb muscle function. Hindlimb muscles (except soleus) were dominated by Type IIB fibers, which were largest in cross-sectional area, and are known to be best suited for rapid and explosive movements. Oxidative Type IIA and Type IIX fibers were found at moderate concentrations and likely function in maintaining continual saltatory locomotion. Thus, kangaroo rats can use these two fiber type populations as “gears” for both endurant and explosive behaviors.     

Histochemical differentiation of fibers in the rat slow and fast twitch muscles.

Wistar male rats were sacrificed at 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and 21 days, and at 5 and 10 weeks of age. The histochemical differentiation of slow twitch soleus and fast twitch plantaris muscle fibers was examined from the enzyme activities of adenosine triphosphatase (slow- or fast-contracting), succinate dehydrogenase (high- or low-oxidative), and alpha-glycerophosphate dehydrogenase (high- or low-glycolytic). The soleus muscle fibers differentiated into slow-contracting (S) and fast-contracting (F) fibers at 7 days of age. In the plantaris muscle, differentiation into S and F fibers in the deep portion occurred earlier (9 days) than in the superficial portion (11 days). Thereafter, fiber type shifts between S and F were observed in both muscles. Differentiation into fast-contracting oxidative glycolytic (FOG), fast-contracting glycolytic (FG), and slow-contracting oxidative (SO) fibers occurred in both muscles at 15 and 17 days of age. After subdivision into the three fiber types, a type shift from FOG to FG was observed in both the deep and superficial portions of the plantaris muscle.     

Scanning electron microscope study of neuromuscular junctions in different muscle fiber types in the zebra finch and rat

Examination by scanning electron microscopy revealed differences between neuromuscular junctions in the muscle fibers of the zebra finch (bird) and rat. The neuromuscular junctions between the anterior and posterior latissimus dorsi muscles of the zebra finch were compared. The junctions of the former, exclusively slow tonic fibers, were small and numerous along the long axis of a single muscle fiber. The synaptic depressions per junction were few. The junctions of the latter, exclusively fast twitch fibers, were large and consisted of more synaptic depressions than the former. Junctional folds were occasionally found in some depressions. The neuromuscular junctions between the extensor digitorum longus and soleus muscles of the rat were also compared. The former consisted almost entirely of fast twitch muscle fibers, whereas the latter consisted of both slow twitch fibers (75%) and fast twitch fibers (25%). The junctions in the extensor digitorum longus muscle were almost all labyrinthine gutters containing exclusively slit-like junctional folds. In the soleus muscle, two types of junctions were observed. One type was similar to that of the extensor digitorum longus muscle; the other was characterized by labyrinthine gutters containing sparse, narrow slit-like and pit-like junctional folds. We suggest from these structural differences of the subneural apparatuses that the junction of the fast twitch muscle is characterized by the subneural apparatus containing numerous slit-like junctional folds, and that of the slow twitch muscle fiber characterized by the apparatus containing sparse, narrow slit-like and pit-like junctional folds.     

Regional differences in fiber characteristics in the rat temporalis muscle

The behavioral differences in muscle use are related to the fiber type composition of the muscles among other variables. The aim of this study was to examine the degree of heterogeneity in the fiber type composition in the rat temporalis muscle. The temporalis muscle was taken from 10‐week‐old Wistar strain male rats (n = 5). Fiber types were classified by immunohistochemical staining according to their myosin heavy chain content. The anterior temporalis revealed an obvious regional difference of the fiber type distribution, whereas the posterior temporalis was homogeneous. The deep anterior temporalis showed a predominant proportion of type IIA fibers and was the only muscle portion displaying slow type fibers (< 10%). The other two muscle portions, the superficial anterior and posterior temporalis, did not differ significantly from each other and contained mainly type IIB fibers. Moreover, the deep anterior temporalis was the only muscle portion showing slow type fibers (< 10%). In the deep portion, type IIX fibers revealed the largest cross‐sectional area (1943.1 ± 613.7 µm²), which was significantly (P < 0.01) larger than those of type IIA and I + IIA fibers. The cross‐sectional area of type IIB fibers was the largest in the remaining two muscle portions and was significantly (P < 0.01) larger than that of type IIX fibers. In conclusion, temporalis muscle in rats showed an obvious heterogeneity of fiber type composition and fiber cross‐sectional area, which suggests multiple functions of this muscle.     

Histochennical properties of some jaw muscles of the lizard Tupinambis nigropunctatus (teiidae)

In many vertebrate limb and jaw muscles constituent fibers with differing contractile and metabolic properties are distributed so as to produce distinct intramuscular oxidative and glycolytic regions. The purpose of this investigation was to determine if similar compartmentalization exists in jaw muscles of the teiid lizard Tupinambis nigropunctatus. Nine jaw muscles from two adults and one juvenile were examined, and serial sections from each muscle were analyzed using histochemical techniques to indicate relative contractile, oxidative, and glycolytic capacities of the fibers and their patterns of distribution. Three distinct fiber types were observed. The histochemical profile of type 1 fibers most closely resembled that of tonic muscle fibers, while profiles of type 2 and type 3 fibers corresponded to those of fast-twitch glycolytic (FG) and fast-twitch oxidative (FO) fibers, respectively. Three muscles contained only type 2 (FG) fibers, and two muscles contained a noncompartmentalized mixture of all three fiber types. The remaining four muscles were distinctly compartmentalized, having a small, inneroxidative region containing primarily type 1 (tonic) and type 3 (FO) fibers and a larger, outer region consisting entirely of type 2 (FG) fibers. The possible relationships between fiber types, compartmentalization, and jaw function are discussed.