Evaluation of Vascular Endothelial Growth Factor (VEGF) and Its Family Member Expression After Peripheral Nerve Regeneration and Denervation

Vascular endothelial growth factor (VEGF) represents one of the main factors involved not only in angiogenesis and vasculogenesis but also in neuritogenesis. VEGF plays its function acting via different receptors: VEGF receptor1 (VEGFR-1), VEGF receptor2 (VEGFR-2), VEGF receptor3 (VEGFR-3), and co-receptors Neuropilin-1 (NRP1) and Neuropilin-2 (NRP2). This study reports on the first in vivo analysis of the expression of VEGF and VEGF family molecules in peripheral nerve degeneration and regeneration: for this purpose, different models of nerve lesion in rat were adopted, the median nerve crush injury and the median nerve transaction followed or not by end-to end microsurgical repair. Results obtained by real time polymerase chain reaction showed that VEGF and VEGF family molecules are differentially expressed under regenerating and degenerating condition, furthermore, in order to study the modulation and involvement of these factors in two different regenerative models, crush injury and end-to-end repair, protein expression analysis was evaluated. In addition, immunohistochemical analysis allowed to state a glial localization of VEGF and VEGFR-2 after peripheral nerve crush injury. Finally in vitro assay on primary Schwann cells culture show that VEGF165 stimulation increases Schwann cells migration, a major process in the promotion of neurite outgrowth. Anat Rec, 301:1646-1656, 2018. (c) 2018 Wiley Periodicals, Inc.