Mechanical properties of the sciatic nerve following combined transplantation of analytically extracted acellular allogeneic nerve and adipose-derived mesenchymal stem cells

Abstract Purpose To investigate the effects of Chemically Extracted Acellular Nerves (CEANs) when combined with Adipose-Derived mesenchymal Stem Cell (ADSC) transplantation on the repair of sciatic nerve defects in rabbits. Methods A total of 71 six-month-old Japanese rabbit were used in this study. Twenty rabbits served as sciatic nerve donors, while the other 51 rabbits were randomly divided into Autologous Nerve Transplantation Group (ANT, n=17), CEAN group (n=17) and CEAN-ADSCs group (n=17). In all these groups, the rabbit's left sciatic nerves were injured before the experiment, and the uninjured sciatic nerves on their right side were used as the control (CON). Electrophysiological tests were carried out and sciatic nerves were prepared for histomorphology and stretch testing at 24 weeks post-transplant. Results There were significant differences between ANT and Con groups in amplitude (AMP): P=0.031; motor nerve conduction velocity (MNCV): P=0.029; Maximum stress: P=0.029; and Maximum strain P=0.027. There were also differences between the CEAN and CEAN+ADSCs groups in AMP: P=0.026, MNCV: P=0.024; Maximum stress: P=0.025 and Maximum strain: P=0.030. No significant differences in these parameters were observed when comparing the ANT and CEAN+SACN groups (MNCV: P=0.071) or the CEAN and ANT groups (Maximum stress: P=0.069; Maximum strain P=0.077). Conclusion Addition of ADSCs has a significant impact on the recovery of nerve function, morphology, and tensile mechanical properties following sciatic nerve injury.

Avaliação macroscópica, microscópica e histomorfométrica do tecido cicatricial pós-cirúrgico de eqüinos submetidos a duas técnicas de neurectomia digital / Macroscopic, microscopic, and histomorphometric evaluation of post-operative scar tissue in horses submitted to two techniques for digital neurectomy

Avaliou-se macro e microscopicamente o tecido cicatricial pós-operatório de eqüinos submetidos a duas técnicas de neurectomia digital: guilhotina (TG) e stripping (TS). Decorridos 14 meses das cirurgias, foram colhidas 32 amostras de tecido cicatricial em quatro éguas, que tiveram os membros submetidos a ambas as técnicas. À macroscopia, verificaram-se as dimensões da cicatriz do coto proximal e a distância entre os cotos proximal e distal. À microscopia, foi quantificada a proporção de tecido nervoso regenerado por meio de histomorfometria. Não houve diferença nas dimensões do tecido cicatricial, contudo a distância entre cotos foi 5,6 vezes maior na TS (P<0,001). Histologicamente, observou-se a presença de tecido conjuntivo frouxo e denso, macrófagos e fibras nervosas delgadas em ambas as técnicas cirúrgicas. Estruturas nodulares, compostas por fascículos nervosos, foram visualizadas em 56,2 por cento (9/16) das amostras colhidas em nervos submetidos à TS. As porcentagens médias de tecido nervoso no tecido cicatricial foram de 0,31 por cento na TG e 2,6 por cento na TS (P<0,001). Concluiu-se que o retorno à sensibilidade nervosa deve demorar mais a ocorrer após a TS, devido à maior distância entre cotos. A maior proporção de tecido nervoso sugere que essa técnica favorece a regeneração nervosa.

The post-operative healed tissues in horses submitted to two digital neurectomy techniques, the guilhotine (GT) and the stripping (ST), were evaluated by macroscopy and microscopy. Fourteen months after surgery, 32 samples of scar tissue were collected from four mares that had the members experimentally submitted to both surgical techniques. By macroscopy, the dimensions of the scar tissue of the proximal stump and the distance between nerve stumps were taken. By microscopy, the proportion of nervous tissues in the scar tissue was quantified by histomorphometry. There were no differences between the scar tissue dimensions, but the distance between stumps was 5.6-fold greater in ST subjects. Histologically, connective tissue, macrophages, and thin nervous fibers were observed in scar tissue present in animals of both groups. Nodular structures composed by nervous fascicules were visualized in 56.2 percent (9/16) of the samples collected from the ST group. The mean percentage of the nervous tissue in scar tissue was 0.31 percent in GT samples and 2.6 percent in ST samples (P<0.001). After ST, a longer time to the return of the sensibility may occur due to the greater distance between stumps. However, greater proportion of nervous tissue in the scar tissue suggests that the use of this technique favors nervous regeneration.