Ultrasound-guided plasma rich in growth factors injections and scaffolds hasten motor nerve functional recovery in an ovine model of nerve crush injury.

In the present study we evaluated the motor recovery process of peripheral nerve injury (PNI), based on electrophysiological and histomorphometric criteria, after treatment with plasma rich in growth factors (PRGF) injections and scaffolds in an ovine model. Three groups of sheep underwent a nerve crush lesion: the first group (n = 3) was left to recover spontaneously (SR); the second group was administered saline injections (SI; n = 5) and a third group (n = 6) received PRGF injections and scaffolds immediately after the crush injury. At post-intervention week 8, 70% of sheep in the PRGF group were CMAP-positive, with no electrophysiological response in the rest of the groups. Histomorphometric analysis 12 weeks after the surgical intervention revealed that the average axonal density of the SR (1184 ± 864 axons/µm2 ) and SI (3109 ± 2450 axons/µm2 ) groups was significantly inferior to the control (8427 ± 2433 axons/µm2 ) and also inferior to the PRGF group (5276 ± 4148 axons/µm2 ), showing no significant differences between the control and PRGF groups. The axonal size of the SR and SI groups was significantly smaller compared with the control group (18 ± 4 µm2 ), whereas the axonal size of the PRGF group (6 ± 5 µm2 ) did not show statistical differences from the control. Morphometry of the target muscles indicated that the PRGF group had the lowest percentage volume reduction 12 weeks after the crush injury. The PRGF group had larger muscle fibre areas than the SI and SR groups, although the differences did not reach statistical significance. Overall, these data suggest that the PRGF injections and scaffolds hastened functional axon recovery and dampened atrophy of the target muscles in an ovine model.