We disclose the highest CMAP amplitudes and axonal diameters in the Schwann-like cell autografted group. Our study also reveals unprecedented results on the in vivo maintenance of the stem cells for six weeks in the nerve tissue, which may be related to the superior characteristics of the conduit and extracellular membrane components employed. Prior to surgery, lentivirus-transduced Z-VAD-FMK cell line BMSC (BMSClacZ+) obtained in vitro reacted positively in the colorimetric assay for
lacZ activity, whereas untransduced BMSC did not ( Fig. 1, A and B). BMSClacZ+ differentiated in vitro in cells that were immunostained for beta-galactosidase ( Fig. 1, D, G and J), presented thin and long cell processes ( Fig. 1, H and K, arrows), and expressed the cell markers S100, p75NTR and Oct6 in the nucleus and cytoplasm ( Fig. 1, C, F and I) that were undetectable in undifferentiated cells. At surgery, three animals from group E died
most likely due to hypersensitivity to anesthesia maintenance. On the second day of the postsurgical period, one animal from group D died due to unexplained cause. Data that had been previously obtained for learn more these animals were not considered in this study. Data analyses using the Kruskal–Wallis test disclosed no difference among groups regarding CMAP amplitude or latency prior to neurotmesis and three weeks after surgery (Fig. 2A). On the other hand, CMAP amplitude analyses made in the six-week postsurgical point revealed differences old among the five groups (0.74 mA, 0.76 mA, 0.99 mA, 1.96 mA, 2.73 mA, respectively for groups A, B, C, D and E; p<0.001, Fig. 2A). Assessment by the Mann–Whitney test adjusted by the Bonferroni coefficient (alpha=0.005116)
disclosed a difference between any control group without Matrigel® (A or B) and any group of cell-containing Matrigel® (D or E): p=0.004 for each comparison, A vs. D; A vs. E; B vs. D; and B vs. E ( Fig. 2A). Other possible paired comparisons were not significant. These data indicate that CMAP amplitude is significantly higher for groups D and E six weeks after surgery. At the sixth week, groups D and E presented respectively 44.52% and 72.03% of their pre-injury CMAP amplitude values, whereas groups A, B and C had the ratios of 12.8%, 15.94% and 16.98% in the same period ( Fig. 2A). Therefore, some functional recovery has been observed for each study group. Qualitative histological analyses at the optical microscope of segments proximal and distal to the graft revealed that, in study groups A through D, the facial nerve has been reorganized in one to three fascicles in the distal segment, whereas group-E animals had the injured facial nerve reorganized in two to four fascicles after surgical repair. Nerve fascicles were surrounded by epineurium with fusiform cells. Mild reactive tissue infiltrate has been observed in all groups, though seemingly more intense in groups A and B.