MOESM1 of Whole bone testing in small animals: systematic characterization of the mechanical properties of different rodent bones available for rat fracture models

Additional file 1: Table S1. Data-summary: Radiological and biomechanical results of each bone

Decellularization treatments result in statistically significant reduction of DNA content.

<p>(A) DNA quantification for all groups, described in ng DNA per mg tissue. Statistically significant difference is indicated as *** p<0.001 compared with each treatment group. (B) DNA reduction efficiency (%) in decellularized groups. Values are expressed as mean±SD (n = 4 per group). All groups were compared with each other regarding statistically significant differences. Statistically significant difference of group 7 compared with the 72 h treatment groups (groups 4, 5, 6) was marked with * (p<0.05). The difference between all other groups was not statistically significant.</p

Biomechanical characterization of decellularized enthesis scaffolds.

<p>(A) Decellularized enthesis samples as well as control samples were biomechanically tensile tested in a customized set-up. (B) Tendon and bone part were clamped to the testing device and strain was applied at a constant speed ramp until failure of the specimen. B, I, T represent bone, interface region, and tendon, respectively.</p

Physical treatments investigated in study 2.

<p>Physical treatments investigated in study 2.</p

Chemical treatments for decellularization in study 1.

<p>Chemical treatments for decellularization in study 1.</p

Additional file 1: of Improving results in rat fracture models: enhancing the efficacy of biomechanical testing by a modification of the experimental setup

Supplemental data sheets. (PPTX 35 kb

Masson’s trichrome staining for the collagen structure of entheses.

<p>(A) Control group showing collagen fibers with cells embedded in between. (B, C, D) Collagen alignment of treated samples for group 5, 6, and 10, respectively. Group 10 showed loosened collagen structure and partial ruptures. Cells were completely removed in B, C, and D. Scale bar = 100 μm. T, I, B refer to tendon, interface region, and bone, respectively.</p

Regional difference of cell density in bone, interface, and tendon region after decellularization.

<p>(A) Cell density in bone, tendon, and interface region in decellularized samples from study 1 and 2 groups. For each group, cell density in the interface region was compared to cell density of the other two regions (* p<0.05, ⁺ p<0.01, ^§ p<0.001). (B) H&E staining for control group; cells are distributed throughout the three regions. (C) Cell density reduction by decellularization differs between the regions; cells located in the interface region partially withstand the decellularization process. Scale bars correspond to 100 μm. T, I, B represent tendon, interface region, and bone, respectively.</p

Determination of mechanical properties for Vicryl and Ethisorb scaffolds with and without seeded cells.

<p>The mechanical properties of Vicryl (A) and Ethisorb (B) scaffolds were measured by using a uniaxial test system. Meshes were clamped along their long side with an initial length L₀ of 20 mm. Maximum force values for the two types of scaffolds (both with and without Hs27 cells) were measured in a single experiment at day (d) 1, 3, 6 and 9 and presented graphically (C). All error bars attached to the mean values represent the SEM of five technical replicates (n = 5; two-way ANOVA comparing maximum force values of Vicryl and Ethisorb scaffolds for each time point: ****p<0.00005).</p

Comparison of proliferation activity of Hs27 cells grown on Vicryl and Ethisorb scaffolds.

<p>Hs27 cells were seeded on Vicryl and Ethisorb scaffolds and cultivated for a period of 9 days. At day (d) 1, 3, 6 and 9 the proliferation activity was measured by means of colorimetric WST assay. The results of one experiment are presented as means of absorbance at 450 nm. The error bars represent SEM of five technical replicates (n = 5; two-way ANOVA comparing proliferation activity of cells between Vicryl and Ethisorb for each time point: ****p<0.00005).</p