Construction and effect evaluation of different sciatic nerve injury models in rats.

Background: The most commonly used experimental model for preclinical studies on peripheral nerve regeneration is the sciatic nerve injury model. However, no experimental study has been conducted to evaluate acute injury modes at the same time. Objective: We conducted sciatic nerve transverse injury, clamp injury, keep epineurium and axon cutting injury, and chemical damage injury in rats to evaluate the degree of damage of the four different injury modes and the degree of self-repair after injury. Methods: The sciatic nerve transverse injury model, clamp injury model, keep epineurium injury model, and chemical damage injury model were constructed. Then, the sciatic nerve function was assessed using clinical evaluation methods and electrophysiological examinations, as well as immunofluorescence and axonal counting assessments of the reconstructed nerve pathways. Results: The evaluations showed that the transverse group had the lowest muscle action potential, sciatic functional index, nociceptive threshold, mechanical threshold, rate of wet gastrocnemius muscle weight, area of muscle fiber, and numbers of myelinated nerve fibers. The chemical group had the highest, while the clamp group and the keep epineurium group had medium. Conclusion: Transverse injury models have the most stable effect among all damage models; chemical injury models self-recover quickly and damage incompletely with poor stability of effect; and clamp injury models and keep epineurium injury models have no significant differences in many ways with medium stability.