Peripheral nerve injuries (LNPs) have a high clinical incidence. Complete nerve transection (neurotmesis) results in nerve conduction blockage, causing changes in the peripheral nervous system (PNS) and spinal cord, in which their axons regenerate differently from the original. Complete functional recovery after LNP is a challenge for clinical practice. Nerve reconstruction associated with heterologous fibrin biopolymer (BHF) has shown positive results, but its late and spinal cord effects have not yet been explored. We will investigate the effects of nerve reconstruction via neurorrhaphy (suture) associated with BHF at 120 days after injury and repair of the sciatic nerve in Wistar rats, addressing aspects of the PNS - nerve, neuromuscular junction (NMJ) and muscle - and central (lower motor neurons of the spinal cord). Thirty-two adult male Wistar rats (CEUA 1402/2021) will be distributed in: Control (C), the right sciatic nerve will be visualized; Denervated (D), neurotmesis will be performed with removal of a 6mm fragment; Neurorrhaphy (N) and Neurorrhaphy + BHF (NB) in which, after neurotmesis, the stumps will be reconnected and in the NB group, BHF will be added. At 105 days after LNP, we will apply the neurotracer to the right cranial tibial muscle for retrograde spinal cord marking. At 120 days, spinal cords, fibular nerves and muscles will be collected for the following analyses: morphological and morphometric analysis of the fibular nerve, muscle fibers, JNMs and intramuscular connective tissue; ultrastructural analysis of muscle fibers and JNMs; immunohistochemistry for Fluorogold and GFAP and 3D reconstruction of the ventral column of the spinal cord.
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