Lower trunk of brachial plexus injury in the neonate rat: effects of timing repair

Abstract Objective: After lesion of a peripheral nerve in neonatal mammals, motoneurons undergo a cell death. We wanted to ascertain if early surgery could influence such post-axotomy motoneuronal death and improve the functional outcome. In this study, we investigated the functional and anatomical results after immediate and delayed repair of the lower trunk of brachial plexus (BP) sectioned at birth in rats. Methods: In neonate rats, the lower trunk of the left BP was cut. This nerve trunk was repaired either immediately [immediately-reconstructed group of rats (IR), or 30 days after, tardy reconstructed group of rats (TR)]; in the third group of animals, the nerve was not repaired (noreconstructed group of rats, NoR). In each group of animals, functional studies were performed at 90 days of age using the grooming test and the walking tracks analysis. Histologic studies of the C7–T1 spinal cord and lower trunk of BP were performed at 30 and 90 days of age; the numbers of motoneuron and axon were counted...