Evaluation of developmental changes in the coexpression of myosin heavy chains and metabolic properties of equine skeletal muscle fibers
Evaluation of developmental changes in the coexpression of myosin heavy chains and metabolic properties of equine skeletal muscle fibers
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DOI：
10.2460/ajvr.2005.66.401
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发表时间：
2005-03-01
影响因子：
1
通讯作者：
Miyata, H
中科院分区：
文献类型：
--
作者：
Yamano, S;Eto, D;Miyata, H
目的：研究马肌纤维类型（包括经免疫组织化学鉴定的杂交纤维）代谢和解剖特性的生长相关变化。动物24只2、6、12、24个月大的雌性纯种马。从所有马的臀中肌中获得样本。采用4种一级单克隆抗体BA-D5、SC-71、BF-F3和BF-35分别检测各肌纤维中肌球蛋白重链（MHC）亚型MHC- i、-IIa、-IIb和-IIx的表达。免疫组织化学鉴定了5种肌纤维类型（I型、I/IIA型、IIA型、IIA/IIX型和IIX型）。采用定量组织化学染色和图像分析方法测定各纤维类型中琥珀酸脱氢酶（SDH）的面积和活性。结果-虽然I型和IN型纤维的比例不随年龄变化，但IIA型和IIA/IIX型纤维的比例在2月龄至24月龄期间分别显著增加和减少。随着生长，IIA型纤维比例的增加可能归因于IIA/IIX型纤维的肌纤维类型转变，而不是来自in型纤维。杂交纤维类型的SDH活性和纤维面积值介于各自纯表型的中间。结论与临床意义：杂交纤维在确定< 24月龄马肌纤维类型的比例中具有重要作用，并且与成熟马一样，杂交纤维的代谢和解剖特性具有良好的协调性。
Objective-To determine the growth-related changes in metabolic and anatomic properties in equine muscle fiber type, including hybrid fibers identified with immunohistochemical analysis.Animals 24 2-, 6-, 12-, and 24-month-old female Thoroughbreds.Procedure Samples were obtained from the gluteus medius muscle of all horses. Expression of myosin heavy chain (MHC) isoforms MHC-I, -IIa, -IIb, and -IIx in each muscle fiber was detected by use of 4 primary monoclonal antibodies: BA-D5, SC-71, BF-F3, and BF-35, respectively. Five muscle fiber types (types I, I/IIA, IIA, IIA/IIX, and IIX) were immunohistochemically identified. The area and activity of succinic dehydrogenase (SDH) in each fiber type were determined by use of quantitative histochemical staining and image analysis.Results-Although the proportion of type I and IN fibers did not change with age, the proportion of type IIA and IIA/IIX fibers significantly increased and decreased, respectively, from 2 months to 24 months of age. The increase in proportion of type IIA fibers with growth may have been attributable to muscle fiber-type transition from type IIA/IIX fibers but not from type IN fibers. Values for SDH activity and fiber area in hybrid fiber types were intermediate to those for their respective pure phenotypes.Conclusions and Clinical Relevance-Hybrid fibers have an important role for determining the proportion of muscle fiber type in horses < 24 months old, and the metabolic and anatomic properties of the hybrid fibers are well coordinated, as in mature horses.