Tissue Engineering.

Woo SL-Y, Takakura Y, Liang R, Jia F, Moon D.


Porcine small intestinal submucosa (SIS) was shown to be an effective bio-scaffold in enhancing the mechanical properties of healing medial collateral ligaments (MCL). The purpose of this study was to investigate whether there are corresponding improvements in morphology and tissue compositions. Fourteen rabbits were equally divided into two groups. In the SIS-treated group, a 6 mm gap was surgically created in the right MCL and a layer of SIS was sutured covering the gap. For the untreated group, the gap-injured MCLs remained untreated. All the left MCLs were sham operated and used as controls. At 12 weeks, the status of collagen type I and V were evaluated with hematoxylin & eosin and immunoflurescent staining. The collagen type V/I ratios were obtained using SDS-PAGE. Collagen fibril diameters were calculated from the transmission electron micrographs. The results revealed that in the SIS-treated group, the collagen fibers were more regularly aligned as were the cell nuclei. The collagen fibril diameters were 22.2% larger and the ratio of collagen type V/I was 28.4% lower than those for the non-treated group (p<0.05). These improvements in the morphological characteristics and biochemical constituents of healing MCLs following SIS treatment are the likely reasons for improved mechanical properties.