Peripheral Nerve Injury Models of Neuropathic Pain 

In the sciatic nerve ligation (SNL) model, the L5 and L6 spinal nerves are either cut or tightly ligated, leading to axonal degeneration across all axon types. This results in mechanical allodynia, spontaneous pain, and cold allodynia lasting for months without recovery.

In the standard chronic constriction injury (CCI) model, the left sciatic nerve is ligated, causing inflammation, swelling, and peripheral pain. This method results in a significant reduction of large, myelinated fibers. In this model, the left sciatic nerve is exposed and sutured above the femoral joint in anesthetized animals. Pain behaviors and sensitivity to stimuli is observed following surgery. 

In the crush model, the sciatic nerve is separated near the femoral joint and crushed using non-traumatic clamps. This model integrates in vivo electrophysiology to directly assess nerve conduction and regeneration, alongside behavioral assessments of pain.

In the nerve cuff model, the sciatic nerve is compressed with a polyethylene cuff, producing consistent pain with less variability compared to other peripheral nerve injury models.

In the stretch model, controlled tension is applied to the nerve, causing injury and functional impairment. This model is ideal for evaluating nerve regeneration and long-term recovery, with a slower recovery timeline compared to the crush model.

In the spared nerve injury (SNI) model, the common peroneal and tibial nerves are injured, resulting in partial denervation. This leads to consistent tactile hypersensitivity in the skin territory of the intact sural nerve.

In the distal tibial injury (DTI) model, the tibial nerve is dissected and severed while preserving the popliteal vessels. While many models focus on proximal nerve injuries, this model addresses distal extremity injuries, reflecting the clinical reality where most nerve injuries are distal.

The peripheral neuritis trauma (PNT) model in pigs focuses on inducing neuropathic pain through sciatic nerve trauma. Pigs are ideal for this model due to their anatomical, physiological, and neurological similarities to humans. This model allows researchers to evaluate pain-relieving medications and monitor pain-related behaviors.

MD Biosciences developed and published the pig PNT model:

Open field and a behavior score in PNT model for neuropathic pain in pigs (2018) Journal of Pain Research

Peripheral Neuritis in Pigs: A Neuropathic Pain Model. (2016) Journal of Pain