| 摘要: |
| 【目的】探究胎儿期绵羊肌纤维的形成与发育规律，揭示德国美利奴羊胎儿期骨骼肌的组织学生长发育特征。【方法】选择妊娠期第75天（D75）、第105天（D105）和第135天（D135）的胎羊，测定其体长、体高和体质量；采集背最长肌，进行组织切片和HE染色，统计不同发育阶段胎儿单位肌纤维数量、直径和密度；应用免疫组化方法研究不同发育阶段背最长肌中快/慢肌纤维的类型和密度。【结果】随着怀孕母羊妊娠时间的增加，从75~135 d胎儿体质量增长近17倍，体长、体高增加近1.5倍；单位肌纤维数量总体呈先增加后减少的变化趋势，在105 d时单位面积肌纤维数量最高；肌纤维直径于75~105 d增长幅度较为平缓，105~135 d增长速率明显变大；早中期发育主要以慢肌（Ⅰ型肌纤维）为主，后期发育主要以快肌（Ⅱ型肌纤维）为主。【结论】德国美利奴羊胎儿肌纤维数量在妊娠105 d时达到峰值，且此时肌纤维数量基本恒定，是肌纤维从肌增生转为肌肥大发育的关键时期，早中期发育主要以慢肌（Ⅰ型肌纤维）为主，后期发育主要以快肌（Ⅱ型肌纤维）为主。 |
| 关键词: 德国美利奴羊 胎儿期 骨骼肌 组织学结构 |
| DOI： |
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| 基金项目:国家自然科学基金项目（31560627，U1503285） |
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| Study on structure development characteristics of German Merino sheep fetal skeletal muscle tissue |
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LI Xuejiao,LIU Chenxi,SUN Yawei,et al
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| Abstract: |
| 【Objective】The purpose of this study is to explore the formation and development pattern of muscle fiber and reveal the developmental characteristics of skeletal muscle tissue in fetal period of German Merino sheep.【Method】Three times of D75,D105 and D135 during pregnancy were selected.The body size of German Merino fetal sheep was measured.Longissimus tissue from fetal sheep was collected and subjected to tissue sections and HE staining to count for the fiber number,diameter and density at different developmental stages of fetal muscle tissue.Fiber type was determined using immunohistochemistry to clarify the number of fast/slow muscle fiber type in dfferent stages of development.【Result】At the period from D75 to D135 of pregnant,the increase of fetal weight was nearly 17 times,the body length and height is nearly 1.5 times.The numbers of muscle fibers in unit area gradually increased to D105 while reach the highest value,and the overall trend first climbed up and then declined. The growth rate of diameter of muscle fibers from D75 to D105 was relatively smooth,but that of D105-D135 obviously increased. In middle stage,the slow muscle (type Ⅰ muscle fiber) was the main type,and the latter was mainly composed of fast muscle (type Ⅱ muscle fiber).【Conclusion】The number of German Merino sheep fetal muscle fiber reached peak at D105,and the number of muscle fiber is almost constant.We found that the pregnant time of 105 days was a critical time window with fiber developmental transformation from muscle hyperplasia to muscle hypertrophy,and made clear the slow muscle (type Ⅰ muscle fiber) was the main type during middle stage,and the latter stage was mainly composed of fast muscle (type Ⅱ muscle fiber). |
| Key words: German Merino fetus skeletal muscle histological structure |
