波浪狀微結構和機械拉伸對韌帶纖維母細胞的影響

Abstract

韌帶是由呈現平行的波浪狀結構膠原蛋白纖維所組成,而這種波浪狀結 構被認為是給予韌帶細胞較好的基因表現的主因。在先前的研究中指出,細 胞在有排列的基質上比起沒有排列的,有較好的第一型膠原蛋白基因表現, 而在我們先前的實驗中,把細胞種在波浪狀的電紡絲結構,基因表現比在平 行直線電紡絲中來得好,為了研究這個現象背後的主因,我們製作了直線和 不同曲率彎曲微結構的 PDMS 基質。實驗結果指出,細胞型態在不同的基 質上有顯著性差異存在;在平行直線組別中,細胞擁有最大的細胞以及細胞 核長寬比,而此數據會隨著曲率增加而減少,有趣的是細胞核密度卻和其他 細胞型態沒有明顯的關聯性存在,當我們施加細胞骨架抑制劑後,我們發現 actin 和 intermediate filaments 似乎影響了細胞核結構;另外我們也施加了 拉伸刺激,而這樣的刺激會藉由怎樣的機制影響細胞及其基因表現將會是我 們未來研究的方向。

Native ligament tissues are composed by wavy and parallel type I collagen fibers, and the wavy structures, known as crimp, are hypothesized to be instructive in the ligament phenotype. Previous studies demonstrated that aligned cells had better type I collagen expression than cells on randomly oriented substrates. We previously found that cells on wavy PLLA fibers exhibit enhanced ligament phenotype than on straight fibers. In order to investigate the reason behind this phenomenon, we fabricated PDMS microgroove substrates with straight and wavy structure. The results show that different cell morphologies appear in straight, wavy, and 2X wavy pattern. In straight groups, cells have the largest cell and nuclear aspect ratios, which reduce with increasing curvature. Interestingly, there is no clear correlation between nuclear density and cell morphologies. After inhibitor treatment, it seems that actin and intermediate filaments both affect the nucleus structure. Additionally, we provided tensile loading. We will study the mechanism of tensile loading on cell mechanotransduction and phenotype.