Kim H D
Department of Histology, College of Medicine, Chung-Ang University, Seoul, South Korea.
Anat Rec. 1996 Oct;246(2):271-8. doi: 10.1002/(SICI)1097-0185(199610)246:2<271::AID-AR13>3.0.CO;2-L.
The intermediate filament (IF) desmin provides support for contractile machinery in muscle cells, and vimentin plays an important role in maintaining the stability of mesenchymal cells and in signal transduction. However, development of IFs in heart tissue during intrauterine life in human is not well established.
In the present study, development of desmin and vimentin in human fetal hearts aged 9-28 weeks of gestation (n = 41) were investigated by immunohistochemistry with monoclonal antibodies against desmin and vimentin. Relative density of fluorescence of each sample was determined by densitometry. Left ventricle (LV) tissues from a 1-year-old child (n = 1) were examined by immunohistochemistry for postnatal comparison. Western blot analyses were done with only a few randomly selected LV tissues from fetuses of 9, 20, and 28 weeks gestation to assess trends of desmin and vimentin expression.
By Western blot analyses, 53-kDa desmin and 54-kDa vimentin were present in all fetal heart tissues examined. Desmin intensity was progressively increased with increasing fetal age, whereas vimentin intensity decreased. Desmin was present only in cardiomyocytes. In the earlier period (10-14 weeks gestation), desmin was localized along the cardiomyocyte membrane and/or Z lines in regular intervals, and later (25-28 weeks gestation) it was structurally well integrated; however, its network was incomplete. Only cardiomyocytes from a 1-year-old child revealed highly developed and integrated desmin lattices. However, vimentin was present in the mesenchymal tissue including fibroblasts and surrounding blood vessels. In part, some cardiomyocytes showed a weakly positive reaction with monoclonal antibody against vimentin in 9-14 weeks gestation. Vimentin-positive areas, however, were progressively diminished with increasing fetal age. Vimentin was present only in the connective tissue and coverings of the 1-year-old child's heart. Relative density of fluorescence of desmin was increased with increasing fetal age, whereas that of vimentin decreased.
These results indicate that there is a fetal age (or gestation)-dependent expression of IFs in human fetal heart: desmin increases with increasing fetal age, whereas vimentin decreases.
中间丝（IF）结蛋白为肌肉细胞中的收缩机制提供支撑，波形蛋白在维持间充质细胞稳定性及信号转导中发挥重要作用。然而，人类子宫内发育期间心脏组织中中间丝的发育情况尚未完全明确。
在本研究中，采用抗结蛋白和波形蛋白的单克隆抗体，通过免疫组织化学方法研究了41例孕龄9 - 28周的人类胎儿心脏中结蛋白和波形蛋白的发育情况。通过光密度测定法确定每个样本的荧光相对密度。对一名1岁儿童的左心室（LV）组织（n = 1）进行免疫组织化学检查以作出生后对比。仅对9周、20周和28周孕龄胎儿的少数随机选取的LV组织进行蛋白质免疫印迹分析，以评估结蛋白和波形蛋白的表达趋势。
通过蛋白质免疫印迹分析，在所检测的所有胎儿心脏组织中均存在53 kDa的结蛋白和54 kDa的波形蛋白。结蛋白强度随胎龄增加而逐渐增加，而波形蛋白强度则降低。结蛋白仅存在于心肌细胞中。在早期（孕10 - 14周），结蛋白沿心肌细胞膜和/或Z线呈规则间隔分布，后期（孕25 - 28周）其结构整合良好，但网络不完整。仅1岁儿童的心肌细胞显示出高度发达且整合良好的结蛋白晶格。然而，波形蛋白存在于包括成纤维细胞和周围血管在内的间充质组织中。部分心肌细胞在孕9 - 14周时对波形蛋白单克隆抗体呈弱阳性反应。然而，波形蛋白阳性区域随胎龄增加而逐渐减少。波形蛋白仅存在于1岁儿童心脏的结缔组织和被膜中。结蛋白的荧光相对密度随胎龄增加而增加，而波形蛋白的荧光相对密度则降低。
这些结果表明，人类胎儿心脏中中间丝的表达存在胎龄（或孕周）依赖性：结蛋白随胎龄增加而增加，而波形蛋白则减少。
