Characterization of the content and distribution of collagen and proteoglycan in the decellularized book-shaped enthesis scaffolds by SR-FTIR

Background: Bone-tendon interface (enthesis) plays a pivotal role in relaxing load transfer between otherwise structurally and functionally distinct tissue types. Currently, decellularized extracellular matrix (DEM) from enthesis provide a natural three-dimensional scaffold with tissue-specific orientations of extracellular matrix molecules for enthesis regeneration, however, the content and distribution of collagen and proteoglycan in the decellularized book-shaped enthesis scaffolds from rabbit rotator cuff by SR-FTIR have not been reported. Methods: : Native enthesis tissues (NET) harvested from rabbit rotator cuff were sectioned into cuboid (about 30 mm × 1.2 mm × 10 mm) for decalcified. The decellularized book-shaped enthesis scaffolds were conducted and intrinsic ultrastructure was evaluated by histological staining and scanning electron microscopy (SEM), respectively. The content and distribution of collagen and proteoglycan in the decellularized book-shaped enthesis scaffolds from rabbit rotator cuff were also measured innovatively by SR-FTIR. Results: : The decellularized book-shaped enthesis scaffolds from rabbit rotator cuff were successfully obtaine©d. Histomorphology and SEM evaluated the decellularized effect and the structure of extracellular matrix during decellularization. After mechanical test, we found the failure load in the NET group was higher than that in the DEM group (P < 0.05), reached 1.32 times as much as that in the DEM group. Meanwhile, the stiffness of the DEM group was significantly lower than the NET group. Furthermore, the distributions of collagen and PGs content in the decellularized book-shaped enthesis scaffolds were decreased obviously after decellularization by SR-FTIR quantitative analysis. Conclusion: SR-FTIR was applied innovatively to characterize the histological morphology of native enthesis tissues from rabbit rotator cuff. Moreover, it can be used for quantitative mapping of the content and distribution of collagen and PGs content in the decellularized book-shaped enthesis scaffolds.