不同发育期大通牦牛心肌、骨骼肌线粒体ATP酶活性的测定

对青海省大通牦牛1、30、180日龄及成年组心肌和骨骼肌线粒体Na+-K+-ATP酶、Mg2+-ATP酶、Ca2+-ATP酶和Ca2+-Mg2+-ATP酶活性进行测定。结果显示,牦牛心肌、骨骼肌线粒体Na+-K+-ATP酶、Mg2+-ATP酶、Ca2+-ATP酶和Ca2+-Mg2+-ATP酶活性在年龄组间差异均不显著(P>0.05)。表明大通牦牛在生长发育阶段心肌、骨骼肌线粒体ATP酶在物质运输、能量转换及信息传递等方面发挥着稳定的作用,且与年龄之间无明显的线性关系。     

不同海拔地区牦牛心肌、骨骼肌GSH-PX的测定

在西宁屠宰场对来自青海省两个不同海拔县牦牛心肌和骨骼肌线粒体内谷胱甘肽过氧化物酶(GSH-PX)活性进行测定。结果表明,海拔4300m左右的玛多县牦牛心肌、骨骼肌GSH-PX分别为20.15U.mg-1±5.43U.mg-1和15.32U.mg-1±4.27U.mg-1,海拔3400m左右的刚察县牦牛心肌、骨骼肌GSH-PX分别为6.67U.mg-1±5.67U.mg-1和7.76U.mg-1±4.83U.mg-1;玛多牦牛的心肌、骨骼肌组织线粒体的GSH-PX活性显著高于刚察牦牛(P<0.05)。在高原低氧环境下,牦牛体内GSH-PX活性与海拔高度呈正相关。     

不同海拔地区牦牛心肌、骨骼肌线粒体标志酶的测定

采用酶联免疫分析法(ELISA)和比色法对青海省泽库、海晏县牦牛心肌和骨骼肌线粒体标志酶琥珀酸脱氢酶(SDH)、细胞色素氧化酶(CCO)和三磷酸腺苷(ATP)活性进行测定,并与甘肃黄牛进行对比。结果显示:泽库牦牛心肌、骨骼肌线粒体SDH、ATP活性显著高于海晏牦牛和甘肃黄牛(P<0.05),而海晏牦牛和甘肃黄牛差异不显著(P>0.05);泽库、海晏牦牛和甘肃黄牛心肌、骨骼肌线粒体CCO活性差异均不显著(P>0.05)。表明随着海拔的升高,牦牛心肌、骨骼肌线粒体标志酶SDH、ATP表达量增加,肌组织有氧代谢能力增强。     

不同地区牦牛心肌、骨骼肌CCO、SDH活性测定

为了进一步从细胞分子水平探讨牦牛高原低氧适应的生物学机制以及为高原疾病的诊疗提供理论依据,试验采用酶联免疫法测定了青海省玛多县、泽库县牦牛的心肌、骨骼肌组织及其线粒体中细胞色素氧化酶(CCO)和琥珀酸脱氢酶(SDH)的活性。结果表明:玛多牦牛心肌、骨骼肌线粒体中SDH活性均高于泽库牦牛,玛多、泽库牦牛骨骼肌线粒体中SDH活性差异显著(P<0.05),泽库牦牛心肌、骨骼肌组织SDH活性均高于其线粒体中SDH的活性,且差异极显著(P<0.01);玛多、泽库牦牛心肌、骨骼肌线粒体中CCO活性差异不显著(P>0.05),泽库心肌、骨骼肌组织中CCO活性显著或极显著高于线粒体中CCO的活性(P<0.05或P<0.01)。在高原低氧环境下,随着海拔的升高,牦牛心肌、骨骼肌组织及其线粒体中SDH活性增强,而CCO有氧代谢保持相对稳定的水平,表明牦牛对高原低氧环境具有显著的适应性。     

“大通牦牛”胎盘-胎儿组织线粒体SDH、CCO和ATP酶活性的测定

为探究牦牛发育早期低氧适应的生物学机制,以"大通牦牛"(海拔3 200 m左右)为研究对象,采用酶联免疫分析法(ELISA)和比色法对妊娠期4月龄牦牛胎盘、胎儿及出生1日龄牦牛组织中琥珀酸脱氢酶(SDH)、细胞色素C氧化酶(CCO)及三磷酸腺苷(ATP)酶活性进行测定。结果:胎儿和犊牦牛骨骼肌、心肌、肝脏及大脑各组织线粒体SDH、CCO活性差异均不显著(P>0.05);妊娠4月龄胎盘组织和胎儿肝脏组织线粒体中Na+-K+-ATP、Mg2+-ATP、Ca2+-ATP和Ca2+-Mg2+-ATP 4种ATP酶活性均高于心肌、骨骼肌、大脑组织,差异显著(P<0.05);出生1日龄牦牛骨骼肌、心肌、肝脏及大脑各组织间4种ATP酶差异不显著(P>0.05),各组织中Ca2+-Mg2+-ATP酶活性均高于其他ATP酶活性。研究表明牦牛在发育早期组织线粒体中SDH、CCO保持相对稳定的水平,而ATP酶在物质运送、能量转换以及信息传递方面发挥重要的作用。     

高原牦牛 黄牛心肌及骨骼肌线粒体抗氧化作用的比较研究

采用酶联免疫分析法(ELISA)和比色法对高原牦牛和黄牛心肌、骨骼肌线粒体琥珀酸脱氢酶(SDH)、细胞色素氧化酶(CCO)、三磷酸腺苷(ATP)、氧化物歧化酶(T-SOD)及丙二醛(MDA)指标进行测定。结果显示,高原牦牛与黄牛心肌、骨骼肌线粒体ATP、SDH、CCO、T-SOD酶活性及MDA含量差异均不显著(P0.05);高原牦牛与黄牛心肌、骨骼肌胞浆SDH、CCO活性均高于线粒体(P0.05)。     

不同海拔牦牛骨骼肌线粒体呼吸链复合酶活性及氧化应激指标的差异分析

线粒体呼吸链是实现氧化磷酸化的分子机构,被广泛证实是活性氧产生的主要来源,活性氧的积累会造成细胞氧化应激,因此为了阐明不同海拔地区牦牛骨骼肌线粒体呼吸链复合酶活性及抗氧化能力的差异,试验从高(海拔4 200 m)、中(海拔3 200 m)、低(海拔1 900 m)海拔地区随机选择临床健康成年雄性牦牛各5头(分别分为高、中、低海拔组),屠宰后取骨骼肌采用比色法测定5种线粒体呼吸链复合酶和抗氧化关键酶的活性及氧化应激指标。结果表明：随着海拔的升高,牦牛骨骼肌线粒体呼吸链复合酶Ⅰ～Ⅴ活性均表现为逐渐降低的趋势,其中高海拔组牦牛骨骼肌线粒体呼吸链复合酶Ⅰ、Ⅲ、Ⅳ活性与中、低海拔组牦牛差异显著(P<0.05);低海拔组牦牛骨骼肌线粒体呼吸链复合酶Ⅱ、Ⅴ活性与中、高海拔组牦牛差异显著(P<0.05)。随着海拔的升高,牦牛骨骼肌中羟自由基、丙二醛(MDA)含量和谷胱甘肽过氧化物酶(GSH-Px)活性逐渐下降,且各组间显著差异(P<0.05);总抗氧化能力(T-AOC)先升高后降低,中海拔组牦牛骨骼肌显著高于低海拔组和高海拔组(P<0.05);超氧化物歧化酶(SOD)活性先下降...     

不同海拔地区牦牛心肌、骨骼肌线粒体氧自由基代谢的研究

对青海省玛多和刚察两县牦牛心肌、骨骼肌组织中肌红蛋白(Mb),心肌、骨骼肌中线粒体总抗氧化能力(T-AOC),超氧化物歧化酶(SOD),谷胱甘肽过氧化物酶(GSH-PX),乳酸脱氢酶(LDH)活性及丙二醛(MDA)含量进行了测定。结果:玛多牦牛心肌、骨骼肌中Mb含量均高于刚察牦牛,但差异不显著(P0.05);玛多牦牛心肌、骨骼肌线粒体中T-AOC,SOD,GSH-PX酶活性均显著高于刚察牦牛(P0.05),而LDH活性显著低于刚察牦牛(P0.05),玛多牦牛骨骼肌和心肌线粒体MDA含量低于刚察牦牛(P0.05)。结论:在高原低氧环境下,牦牛心肌、骨骼肌线粒体抗氧化能力随海拔高度的升高而增强,表明牦牛对高原低氧环境具有显著的适应性。     

不同海拔地区牦牛骨骼肌组织结构比较

为了探讨高原牦牛骨骼肌组织对低氧环境的适应,选取不同海拔梯度牦牛骨骼肌组织进行研究。结果表明,果洛牦牛骨骼肌纤维直径细于泽库牦牛,肌纤维表面积密度大于泽库牦牛,差异显著(P<0.05);果洛牦牛骨骼肌线粒体平均截面积、平均体积和面数密度均大于泽库牦牛,差异显著(P<0.05)。这些组织学改变是机体为了适应高海拔低氧环境,为了增加氧的利用而做出的组织学的改变和适应。大通牦牛骨骼肌各项指标表现出一定的特殊性,这与大通牦牛为改良品种有关。     

不同海拔牦牛骨骼肌代谢关键酶比较分析

为分析不同海拔牦牛骨骼肌代谢关键酶的含量及其酶活性,本试验选取3个海拔高度(4 200、3 200和1 900 m)的牦牛作为研究对象,其中低海拔牦牛作为对照,运用电镜技术观测牦牛骨骼肌的线粒体相关指标,运用ELISA方法测定骨骼肌代谢关键酶乳酸脱氢酶(LDH)和琥珀酸脱氢酶(SDH)的含量、酶活性和LDH同工酶类型。结果显示,随海拔升高,肌红蛋白(Mb)和有氧代谢关键酶SDH含量和酶活性逐渐增强,中海拔和高海拔牦牛的Mb含量和SDH酶活性均高于低海拔牦牛且差异显著(P<0.05),高海拔牦牛SDH含量大于低海拔牦牛且差异显著(P<0.05);随海拔升高,无氧代谢关键酶LDH含量和酶活性逐渐降低,中海拔和高海拔牦牛LDH含量和酶活性均低于低海拔牦牛且差异显著(P<0.05);3个不同海拔牦牛5种LDH同工酶中LDH5占比最高,随着海拔升高,LDH1、LDH2、LDH4和LDH5含量逐渐下降,中海拔和高海拔牦牛LDH1和LDH2含量均低于低海拔牦牛且差异显著(P<0.05),高海拔牦牛LDH4和LDH5含量均低于低海拔牦牛且差异显著(P<0.05)。结果表明...     

不同海拔梯度大通牦牛心肌组织低氧适应的组织学特点

为了进一步研究大通牦牛心肌对高原低氧适应的组织学特点,选取2个海拔高度(海拔3 700,3 200m)成年大通牦牛作为研究对象,并选取同海拔高度的泽库地区成年牦牛(海拔3 700m)和海晏地区成年牦牛(海拔3 200 m)作为对照,利用组织学、免疫组织化和电镜技术对心肌组织的显微和超微结构进行观测与分析,结果显示:海拔3 700m牦牛,其心肌纤维直径细于海拔3 200m牦牛,表面积密度大于海拔3 200m牦牛,差异显著(P0.05);海拔3 700m牦牛血管内皮生长因子(VEGF)和微血管密度(MVD)均大于海拔3 200m牦牛,差异显著(P0.05);海拔3 700m牦牛平均体积和体密度大于海拔3 200m牦牛,差异显著(P0.05);而面数密度(NA)小于海拔3 200m牦牛,差异显著(P0.05)。大通牦牛心肌适应高原低氧环境的组织学特点主要表现为:肌纤维直径细、表面积密度大、VEGF和MVD均较高的特点,心肌肌线粒体平均体积相对较小、NA相对较大,而体密度大的特点。     

大通牦牛心肌线粒体超微结构增龄性变化特点及低氧适应

为了探讨大通牦牛心肌组织对低氧环境的适应机制。选取大通牦牛作为研究对象,以平原黄牛作对照,通过显微体视学技术比较骨骼肌线粒体的平均截面积(Ax)、平均体积(V)、面数密度(NA,单位面积中线粒体数目)、体积密度(VV,单位体积骨骼肌纤维中线粒体的体积密度)。结果显示,大通牦牛心肌线粒体的平均截面积、平均体积随着年龄的增长,表现为逐渐降低的特点;而面数密度表现为随着年龄增长呈现逐渐升高的变化特点;体密度表现为随着年龄的增长逐渐增加,各年龄段差异显著(P0.05);大通牦牛心肌线粒体与同日龄平原黄牛比,表现为线粒体大、数量少和体密度大的特点,差异极显著(P0.01)。结果表明,大通牦牛心肌线粒体在出生时已表现出对高原低氧环境的良好适应性,表现为骨骼肌线粒体平均体积大、面数密度低、体密度高的特点;而在个体生长发育过程中,大通牦牛心肌线粒体平均体积逐渐变小、面数密度逐渐增大,而体积密度逐渐增大的特点,这种变化特点可以满足机体生长发育的需要和对外界环境的适应。     

大通牦牛骨骼肌低氧适应的组织学特点

选取2个海拔高度(3 200、3 700m)大通牦牛作为研究对象,以乐都地区(3 200m)牦牛为对照,利用光镜和计算机图像分析系统测定骨骼肌肌纤维直径、表面积密度;通过透射电镜比较骨骼肌线粒体的面数密度、体积质量、平均体积等结构参数。利用免疫组织化学技术测定骨骼肌组织血管内皮生长因子(Vascular endothelial growth factor,VEGF)和微血管密度(Microvessel density,MVD)。结果显示:(1)2个海拔高度的大通牦牛骨骼肌肌纤维直径均细于乐都牦牛骨骼肌肌纤维直径,差异显著(P0.05),肌纤维表面积密度,大通牦牛均大于乐都牦牛,差异显著(P0.05);(2)2个海拔高度的大通牦牛VEGF和MVD均高于乐都牦牛的VEGF和MVD,差异显著(P0.05);(3)海拔3 700m的大通牦牛骨骼肌线粒体平均体积、体积质量和面数密度均大于海拔3 200m的大通牦牛和乐都牦牛的平均体积、体积质量和面数密度,差异显著(P0.05)。结果表明:大通牦牛骨骼肌组织有良好的组织遗传学特性,表现出其育种父本的特征及对高原低氧环境的良好适应性,主要表现为肌纤维直径细、表面积密度大、骨骼肌组织VEGF表达量大和MVD大的特点。而骨骼肌线粒体的超微结构,更多的受环境因素的影响,主要表现为高海拔大通牦牛通过增加骨骼肌线粒体平均截面积、平均体积、体积密度和面数密度来提高其在低氧环境中对氧的利用。     

大通牦牛心肌低氧适应的组织学特点

选取两个海拔高度大通牦牛作为研究对象,以乐都地区牦牛为对照,利用光镜技术和计算机图像分析系统测定心肌肌纤维直径、表面积密度;利用透射电镜技术比较心肌线粒体的平均体积(V)、体积密度(VV)和面数密度(NA)等结构参数;利用免疫组织化学技术对心肌细胞血管内皮生长因子(VEGF)和微血管密度(MVD)进行检测,并对以上数据进行相关性分析。结果显示:(1)大通牦牛心肌肌纤维直径均细于乐都地区牦牛心肌肌纤维直径,肌纤维表面积密度均高于乐都地区牦牛,且三者两两比较差异显著(P<0.05);(2)大通牦牛的VEGF和MVD均高于乐都地区牦牛,差异显著(P<0.05);(3)大通牦牛心肌线粒体的V和VV均大于乐都地区牦牛,差异显著(P<0.05);海拔3 700m的大通牦牛心肌线粒体面数密度大于海拔3 200m的乐都地区牦牛,差异显著(P<0.05)。结果表明,大通牦牛心肌组织主要表现为心肌纤维直径细、表面积密度大、心肌组织血管内皮生长因子和微血管密度大的遗传学特点。而心肌线粒体的低氧适应表现为,随着海拔高度的增加,心肌线粒体平均体积增大,面数密度和体密度增加的特点。     

Extraction and characterization of collagens from yak rumen smooth muscle

This study reports an effective method using enzymatic methods to extract collagen from yak rumen smooth muscle. The enzymatic extraction methods were optimized by response surface methodology. Additionally, the properties of the extracted collagen were analyzed by Fourier transform infrared (FT‐IR) spectroscopy and mass spectrometry (MS). The results showed that the optimal conditions were as follows: the pepsin addition was 0.95%, the enzymatic hydrolysis time was 21 hr, and the solid‐to‐solvent ratio was 1:11. Under these conditions, the collagen extraction rate could reach 3.62/100 g. The results of FT‐IR revealed that the amide A, amide B, amide I, amide II, and amide III bands of the collagen appeared at 3,293.18, 3,068.18, 1654.94, 1,540.58, and 1,236.58 cm^?1, respectively. The MS identified seven types of collagen, which were type I, type III, type IV, type V, type VI, type VIII, and type XII. The results demonstrated that the enzymatic method can extract collagen from yak rumen smooth muscle with a considerably high yield and can preserve the intact structure of the collagen.     

Differentiation of skeletal muscle Mesenchymal progenitor cells to myofibroblasts is reversible

Accumulation of intramuscular adipose tissue (IMAT) and development of fibrous tissues due to accumulation of collagen both affect meat quality such as tenderness, texture, and flavor. Thus, it is important for the production of high‐quality meat to regulate the amount of adipose and fibrous tissues in skeletal muscle. IMAT is comprised of adipocytes, while collagens included in fibrous tissues are mainly produced by activated fibroblasts. Both adipocytes and fibroblasts are differentiated from their common ancestors, called mesenchymal progenitor cells (MPC). We previously established rat MPC clone, 2G11 cells. As several reports implicated the plasticity of fibroblast differentiation, in the present study, using 2G11 cells, we asked whether myofibroblasts differentiated from MPC are capable of re‐gaining adipogenic potential in vitro. By treating with bFGF, their αSMA expression was reduced and adipogenic potential was restored partially. Furthermore, by lowering cell density together with bFGF treatment, 2G11 cell‐derived myofibroblasts lost αSMA expression and showed the highest adipogenic potential, and this was along with their morphological change from flattened‐ to spindle‐like shape, which is typically observed with MPC. These results indicated that MPC‐derived myofibroblasts could re‐acquire adipogenic potential, possibly mediated through returning to an undifferentiated MPC‐like state.     

Light and electron microscopic changes in cardiac and skeletal muscle of sheep with experimental monensin toxicosis

Monensin toxicosis was induced in lambs by either a single oral dose of 12 mg/kg or six daily doses of 8 mg/kg. Clinical signs of toxicosis consisted of depression, dyspnea, stiffness of gait, reluctance to move, and recumbency. Serum creatine phosphokinase activity was increased. Samples of skeletal and cardiac muscle were obtained over a six-day period and examined by light and electron microscopy. Light microscopic changes in cardiac and skeletal muscles consisted initially of vacuolation and intracellular edema of muscle cells followed by segmental necrosis. Interstitial fibrosis was present on days 5 and 6 postexposure. Muscle fiber necrosis was more severe in skeletal than cardiac muscles and most severe in sheep given 8 mg/kg of monensin daily. Macrophages were seen only in areas of severe necrosis. The earliest ultrastructural change was severe swelling of mitochondria. Secondary changes consisted of lipid accumulation and myofibrillar alterations. Myoblast proliferation was present as early as four days after initial exposure to monensin.     

Comparison of enzyme activities and gene expression profiling between yak and bovine skeletal muscles

The objective of the present study was to reveal the differences between yak (Bos grunniens) and cattle in energy metabolic characteristics and gene expressions in skeletal muscles. Activities of lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and β-hydroxyacyl-CoA dehydrogenase (HOAD), which are involved in metabolism of carbohydrate and fatty acid respectively, were measured in longissimus dorsi and biceps femoris. Yak contained higher total LDH activity and higher proportion of LDH5 in longissimus dorsi than cattle (P < 0.05), indicating its more anaerobic potential characteristics in carbohydrate metabolism. However, yak contained higher activities of MDH and HOAD (P < 0.05) in biceps femoris than cattle, exhibiting high oxidative capacity under hypoxic environment. Semi-quantitative RT-PCR analysis of mRNA abundance showed that yak and cattle contained a similar level of adipocyte fatty acid-binding protein (A-FABP) in both longissimus dorsi and biceps femoris, while myosin heavy chain I (MyHC I) in longissimus dorsi and biceps femoris, and peroxisome proliferator-activated receptor coactivator 1α (PGC-1α) level in biceps femoris were significant lower in yak compared with cattle (P < 0.01 and P < 0.05 respectively), indicating the anaerobic characteristic of yak skeletal muscles. In conclusion, our experiment showed that yak skeletal muscles exhibit different energy metabolic property and gene expressions compared to cattle.