Department of Urology, Shiga University of Medical Science, Seta Tsukinowa, Otsu, Shiga 610-0321, Japan.
Division of Medical Life System, Department of Life and Medical Science, Doshisha University, Kyotanabe, Kyoto 610-0394, Japan.
ACS Appl Bio Mater. 2021 Sep 20;4(9):6924-6936. doi: 10.1021/acsabm.1c00572. Epub 2021 Aug 20.
By mimicking the extracellular matrix, nonwoven fabrics can function as scaffolds for tissue engineering application ideally, and they have been characterized regarding their fiber diameter and fiber spacing (spacing size) in vitro. We chronologically examined the in vivo effects of these fabrics on the cellular response and tissue remodeling. Four types of nonwoven polyglycolic acid fabrics (Fabric-0.7, Fabric-0.9, Fabric-3, and Fabric-16 with fiber diameters of 0.7, 0.9, 3.0, and 16.2 μm and spacing sizes of 2.0, 19.3, 19.0, and 825.4 μm, respectively) were implanted into the rat dorsum and subjected to histologic and immunohistochemical analyses from day 3 to 70. With Fabric-0.7, inflammatory cells (mainly M1 macrophages) and myofibroblasts with collagen type III accumulated mainly on the surface of the fabric and did not infiltrate inside the fabric initially, likely due to the narrow fiber space. Massive formation of collagen type I then appeared with the degradation of the fabrics, and finally, the remodeled tissue turned into a dense scar. With Fabric-0.9 and Fabric-3, inflammatory cells (predominantly M2 macrophages) were seen in all layers of the fabric initially. A mild increase in collagen type I was then seen, with few myofibroblasts, and the remodeled tissue ultimately showed a relatively little scar with an adequate thickness of the tissue induced by the fabrics. With Fabric-16, inflammatory cells (predominantly M1 macrophages) infiltrated into all layers of the fabric initially along with many myofibroblasts, especially in the hole. Lately, massive formation of collagen type I was noted due to the slow degradation of the fabric, with the shrinking of the fabric substantially, and the remodeled tissue finally turned to a dense scar. These findings suggest that optimizing the spacing size as well as the fiber diameter of artificial scaffolds may control the cellular response and tissue remodeling and facilitate favorable tissue regeneration without scar formation.
通过模拟细胞外基质，无纺织物可以作为组织工程应用的支架，它们的纤维直径和纤维间距（间距大小）已在体外进行了表征。我们按时间顺序检查了这些织物对细胞反应和组织重塑的体内影响。将四种不同类型的聚乙二醇酸无纺织物（纤维直径分别为 0.7、0.9、3.0 和 16.2μm，间距大小分别为 2.0、19.3、19.0 和 825.4μm 的 Fabric-0.7、Fabric-0.9、Fabric-3 和 Fabric-16）植入大鼠背部，并在第 3 天至第 70 天进行组织学和免疫组织化学分析。在 Fabric-0.7 中，炎症细胞（主要为 M1 巨噬细胞）和肌成纤维细胞最初主要积聚在织物表面，并未最初渗透到织物内部，这可能是由于纤维空间狭窄。随着织物的降解，大量的 I 型胶原形成，最终，重塑的组织变成了致密的疤痕。在 Fabric-0.9 和 Fabric-3 中，最初在织物的所有层中都能看到炎症细胞（主要是 M2 巨噬细胞）。随后，I 型胶原的含量略有增加，肌成纤维细胞较少，最终，由织物诱导的组织具有相对较少的疤痕，并且组织厚度适中。在 Fabric-16 中，炎症细胞（主要是 M1 巨噬细胞）最初沿着织物的所有层渗透，同时还有许多肌成纤维细胞，尤其是在孔中。随后，由于织物降解缓慢，大量的 I 型胶原形成，织物明显收缩，最终，重塑的组织变成了致密的疤痕。这些发现表明，优化人工支架的间距大小和纤维直径可以控制细胞反应和组织重塑，并促进有利的组织再生，而不会形成疤痕。
