Osborn Zoölogical Laboratory of Yale University, New Haven.
J Exp Med. 1915 May 1;21(5):455-78. doi: 10.1084/jem.21.5.455.
In living cultures of various kinds of adult frog tissues, which have been made according to the hanging drop method, there occurs, in many cases, a transformation of the plasma clot by which it becomes entirely changed from a typical fibrin net both in appearance and structure. The changes in the fibrin net generally begin when the culture is from two to three days old. During these changes it appears that the elements of the fibrin net fuse or consolidate, and as a result a great number of fine wavy fibrils are formed which unite to form wavy bundles of fibers, and these freely intertwine and anastomose as they ramify through the area of the plasma clot. The transformation of the fibrin net occurs first in the region of the clot which lies next to the imbedded tissue, gradually extends to the distal regions of the clot, and in time-as a rule in about two weeks-the entire plasma clot becomes changed from the fibrin net into a structure which to all appearances is identical with regular connective tissue. Photographs of both living and preserved cultures have been made to show the course of the transformation of the plasma clot and the development of the fibers. Experiments have been made which show that the fibers which are formed are not outgrowths of the imbedded tissue. Also they are not formed by an intracellular action, but arise directly by a transformation of the fibrin elements of the plasma clot. Experiments have been made which indicate that the transformation of the fibrin net will not occur unless it has come under the influence of living tissues or of living isolated cells. However, mechanical means, such as exerting tension on the clot with needles, may hasten the formation of the fibers. Also, in some cultures, movements of living isolated cells appear to aid in the formation of the fibers. The living tissues alone, however, are able to cause the fibers to form without the aid of any apparent mechanical factor. This is shown by cultures of various tissues in which no cell movement occurs and in which the plasma clot is undisturbed and yet a prolific formation of fibers may take place. Experiments have been made in order to determine the true nature of the transformed plasma clot and to see if the new fibrous tissue were still fibrin in character. The results that have so far been obtained from these tests have not been entirely conclusive and leave the question unsettled. The transformation of the fibrin net results in a shrinkage of the clot. It also becomes very tough and resistant to injury and, therefore, entirely different from the fragile and easily destroyed fibrin net when in its original condition. It is believed that such a reaction must play an important part in wound healing. A study of the relation between connective tissue fibers formed in wound healing and in embryonic development to the fibers formed in the plasma clot is being made, and the results will appear in a later paper.
在各种成年青蛙组织的活体培养物中，按照悬滴法进行培养，在许多情况下，血浆凝块会发生变化，其外观和结构完全从典型的纤维蛋白网转变。纤维蛋白网的变化通常在培养物龄为 2 到 3 天时开始。在这些变化过程中，纤维蛋白网的元素似乎融合或凝聚，结果形成大量的细波状纤维，这些纤维相互结合形成波状纤维束，这些纤维束在穿过血浆凝块的区域时自由交织和吻合。纤维蛋白网的转化首先发生在靠近嵌入组织的凝块区域，逐渐扩展到凝块的远端区域，并且随着时间的推移——通常在大约两周内——整个血浆凝块从纤维蛋白网转变为外观上与规则结缔组织相同的结构。已经制作了活培养物和保存培养物的照片以显示血浆凝块转化和纤维发育的过程。实验表明，形成的纤维不是嵌入组织的延伸物。它们也不是由细胞内作用形成的，而是直接由血浆凝块中纤维蛋白元素的转化形成的。实验表明，除非纤维蛋白网受到活组织或活分离细胞的影响，否则不会发生转化。然而，机械手段，例如用针施加张力于凝块，可以加速纤维的形成。此外，在一些培养物中，活分离细胞的运动似乎有助于纤维的形成。然而，只有活组织能够在没有任何明显机械因素的帮助下引起纤维的形成。这在各种组织的培养物中得到了证明，其中没有细胞运动，并且血浆凝块未被干扰，但大量纤维的形成仍可能发生。已经进行了实验以确定转化后的血浆凝块的真正性质，并观察新的纤维组织是否仍然具有纤维蛋白的性质。到目前为止，从这些测试中获得的结果并不是完全结论性的，因此问题仍未解决。纤维蛋白网的转化导致凝块收缩。它也变得非常坚韧，不易受伤，因此与原始状态下脆弱且易破坏的纤维蛋白网完全不同。人们认为这种反应必须在伤口愈合中发挥重要作用。正在研究伤口愈合和胚胎发育中形成的结缔组织纤维与血浆凝块中形成的纤维之间的关系，结果将在以后的论文中出现。
