A STUDY OF ALTERATIONS OF PLEURAL STRUCTURE BY GROWTH,DEVELOPMENT AND AGING.

胸膜不仅是肺的机械包膜，也是细胞和液体交换的十字路口。我们研究了正常老化过程中的超微结构的变化，在雄性小鼠1天，1周，2周，4周，3个月，6个月，12个月，18个月，24个月，和30个月，扫描和透射电子显微镜。第1天间皮细胞表面微绒毛（SMV）稀疏（密度= 18.2/10 mum^2），然后密度逐渐增加，约18个月时达到平台（D：331.9），此时间皮细胞出现凹凸不平。SMV的长度与密度平行变化（第1天=0.23 mm，1个月=2.27）。24个月后，SMV部分松动（D=241.3），外观不规则且较薄（长度：2.35 μ m）。胸膜结缔组织的形态学特性，包括胶原蛋白，弹性蛋白和成纤维细胞，改变与间皮细胞的变化平行。虽然SMV在胸膜中没有任何已知的功能，但它们随着年龄的变化而变化，可能与胸膜结缔组织的变化以及老化过程中肺实质的结构变化相对应。

The pleura is not only a mechanical envelope for the lung but also represents a crossroad for the exchange of cells and fluids. We studied ultra-structural alterations during normal aging in the visceral pleura of male mice aged 1 day, 1 wk, 2 wks, 4 wks, 3 mos, 6 mos, 12 mos, 18 mos, 24 mos, and 30 mos, by both scanning and transmission electron microscopy. Surface microvilli (SMV) of mesothelial cells appeared sparse at day 1 (density=D : 18.2/10mum^2), then gradually increased in density and reached a plateau at approximately 18 mos (D : 331.9) when the mesothelial cells appeared bumpy. The length of the SMV changed in parallel with density (day 1=0.23 mm, 1 mos=2.27). After 24 mos, the SMV was partially loose (D=241.3), with an irregular and thin appearance (length : 2.35mum). The morphological properties of pleural connective tissues, including collagen, elastin, and fibroblasts, changed in parallel with the changes in mesothelial cells. Although SMV do not have any known functions in the pleura, they changed with age in a manner that likely corresponded to the changes in pleural connective tissue as well as structural changes in lung parenchyma during the aging process.