Morris S M, Thomas K M, Rich C B, Stone P J
Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118, USA.
Anat Rec. 1998 Apr;250(4):397-407. doi: 10.1002/(SICI)1097-0185(199804)250:4<397::AID-AR2>3.0.CO;2-V.
Evidence from in vitro and in vivo studies indicates that damaged elastic fibers can be repaired.
Lipid interstitial pulmonary fibroblasts were cultured for 6 weeks. Cultures were then exposed to 25 microg of porcine pancreatic elastase and fixed in pairs (control, elastase-treated) immediately after exposure and at 1, 2, 3, 4, 7, 10, 14, and 22 days for ultrastructural examination. Elastin was also analyzed biochemically for resistance to hot alkali, an indicator of repair. Steady-state levels of tropoelastin and lysyl oxidase mRNA at 2, 4, and 7 days after elastase treatment were determined by Northern blot analysis.
Immediately after exposure to elastase, damaged elastic fibers exhibited a frayed, porous appearance and a granular texture. Through day 4, fibers showed no evidence of repair. By day 7, the granular texture of damaged fibers was no longer evident and a gradual filling-in of porous areas appeared to be taking place. By 22 days, elastic fibers were indistinguishable from elastic fibers in control cultures. The ultrastructural changes were paralleled by changes in hot alkali resistance. Through day 4, there was no change in the level of hot alkali resistant elastin. Between day 4 and day 7, resistance to hot alkali increased sharply and continued to increase at a slower rate, reaching 84% of the control level by day 22. Steady-state levels of tropoelastin and lysyl oxidase mRNA showed no increase over control levels at 2, 4, and 7 days after elastase treatment.
Elastic fibers synthesized by lipid interstitial pulmonary fibroblasts in culture were repaired after damage by elastase. This type of repair may have relevance to the prevention of pathological conditions, such as emphysema.
体外和体内研究的证据表明受损的弹性纤维可以修复。
培养脂质间质肺成纤维细胞6周。然后将培养物暴露于25微克猪胰弹性蛋白酶，并在暴露后立即以及在第1、2、3、4、7、10、14和22天成对固定（对照、弹性蛋白酶处理组），用于超微结构检查。还对弹性蛋白进行了抗热碱分析，以此作为修复的指标。通过Northern印迹分析确定弹性蛋白酶处理后第2、4和7天原弹性蛋白和赖氨酰氧化酶mRNA的稳态水平。
暴露于弹性蛋白酶后立即观察到，受损的弹性纤维呈现出磨损、多孔的外观和颗粒状纹理。在第4天之前，纤维没有修复迹象。到第7天，受损纤维的颗粒状纹理不再明显，多孔区域似乎开始逐渐填充。到第22天，弹性纤维与对照培养物中的弹性纤维已无法区分。超微结构变化与抗热碱变化平行。在第4天之前，抗热碱弹性蛋白水平没有变化。在第4天至第7天之间，抗热碱能力急剧增加，并继续以较慢速度增加，到第22天达到对照水平的84%。弹性蛋白酶处理后第2、4和7天，原弹性蛋白和赖氨酰氧化酶mRNA的稳态水平没有高于对照水平。
培养的脂质间质肺成纤维细胞合成的弹性纤维在被弹性蛋白酶损伤后得到修复。这种修复类型可能与预防诸如肺气肿等病理状况有关。
