Femke Mathot

Chapter 7 118 Muscle mass (figure 5) At 12 weeks, unseeded allografts measured a significantly lower tibial muscle mass ratio (49.54 ± 2.30%) compared to autografts (59.84 ± 1.64%) (p=0.021). Allografts with undifferentiated and differentiated MSCs measured a muscle mass ratio of 57.68 ± 2.87% and 55.21 ± 2.36% respectively. At 16 weeks, the muscle mass ratio of allografts seeded with undifferentiated MSCs was 59.96 ± 3.79%, which significantly differed from autografts (74.13 ± 1.90%) (p=0.002). Unseeded allografts and allografts seeded with differentiated MSCs had a muscle mass ratio of 69.09 ± 1.54% and 70.09 ± 2.60% respectively. Histology All obtained histology and immunofluorescence values are displayed in table 1 . Figure 6 provides representative nerve sections of the different groups. At 12 weeks, autografts had a significant larger axon area ratio compared to unseeded allografts (p<0.001), allografts seeded with undifferentiated MSCs (p<0.001) and allografts seeded with differentiated MSCs (p=0.004). At 16 weeks, no significant differences in axon area ratio between groups were found. The axon count, myelin area and nerve area measures did not demonstrate any significant differences between groups at any of the time points. Autografts had a significant higher N-ratio compared to unseeded allografts (p=0.023) and allografts seeded with undifferentiated MSCs (p=0.040) at 12 weeks. At 16 weeks, autografts had a significantly better N-ratio compared to unseeded allografts (p=0.003), allografts with undifferentiated MSCs (p=0.025) and allografts with differentiated MSCs (p=0.002) ( figure 7 ). Figure 5. Wet tibial muscle mass ratios (R/L) at 12 and 16 weeks. Autografts showed a significantly higher muscle mass recovery compared to unseeded allografts at 12 weeks, and allografts seeded with undifferentiated MSCs at 16 weeks. uMSCs = undifferentiated Mesenchymal Stem Cells; dMSCs = differentiated Mesenchymal Stem Cells. * = p<0.05, ** = p<0.01, *** = p<0.001. Error bars = Standard error of the mean