Experimental evaluation of nerve graft orientation in a rat model: Functional and histological insights

Abstract

Objectives: This study aims to investigate the effect of nerve graft orientation on nerve regeneration in a rat sciatic nerve defect model and to compare functional and histological outcomes of normal and reverse orientation grafts, focusing on sensory and motor recovery.

Materials and methods: A total of 30 Wistar Albino rats were divided into three equal groups: a control group, a normal graft orientation group (Group A), and a reverse graft orientation group (Group B). A 10-mm sciatic nerve defect was created in the surgical groups, and the graft was applied with epineural coaptation. Functional recovery was evaluated using extensor postural thrust (EPT), pinprick, and hot plate tests, while histological analysis involved axon counts, myelin sheath thickness measurements, and the axon count change ratio.

Results: No significant difference was observed between Group A and Group B in motor function recovery as evaluated by the EPT test (p>0.05). However, Group A showed improved sensory recovery compared to Group B in the pinprick test (p=0.028). Histologically, both groups demonstrated similar ratios of axon count and myelin sheath thickness between proximal and distal segments (p>0.05).

Conclusion: Normal autograft orientation demonstrated superior sensory recovery, while no significant differences were observed in motor function or histological results. These findings highlight the importance of graft orientation for sensory regeneration and underscore the need for future studies to explore the long-term effects of graft orientation and its implications for human nerve repair, particularly in larger defects and clinical scenarios.