Methods for the experimental functional assessment of rat sciatic nerve regeneration

Abstract

In experimental peripheral nerve studies, the rat sciatic nerve model is widely used to examine functional changes after different surgical repairs or pharmacological treatments, following nerve injury. The number and diversity of tests which have been used to assess functional recovery after experimental interventions often makes it difficult to recommend any particular indicator of nerve regeneration. Functional assessment after sciatic nerve lesion has long been focused on walking track analysis, therefore, this article describes in more detail the method to obtain and measure the walking tracks in order to calculate the sciatic functional index (SFI). However, it is important to note that the validity of the SFI has been questioned by several researchers. In addition, the present review includes other traditional tests described in the experimental peripheral nerve literature regarding the rate of return of motor function and sensation, such as the extensor postural thrust (EPT), nociceptive function, and the gastrocnemius-soleus weight parameters. In the last decade, several authors have designed a series of sensitive quantitative methods to assess the recovery of hind limb locomotor function using computerized rat gait analysis. This study aims to review kinematic measures that can be gathered with this technology, including calculation of sciatic functional index, gait-stance duration, ankle kinematics and toe out angle (TOA). A combination of tests, each examining particular components of recovered sensorimotor function is recommended for an overall assessment of rat sciatic nerve regeneration.

Exercício imediato versus tardio na regeneração do nervo isquiático de ratos após axoniotmese: análise histomorfométrica e funcional

“…This is in agreement with several investigators who affirmed that good functional recovery took place over the course of the evaluations, after crushing the sciatic nerve of rats 11,12,24,28 . Therefore, the benefits of physical activity for the denervated animal, such as the increased numbers and diameters of the axons 29 , increased weight, muscle strength, and oxidative capacity of the muscle 10 , rapid return of motor-sensory function during the initial and late phases (thereby accelerating functional recovery) 9 and increased myelinization of the fibers 12 , among others, reaffirmed the importance of investigating and discussing clinical practice.…”

“…Electrophysiology, histomorphometry and functional tests have been greatly used to quantify nerve regeneration in experimental studies, because they make it possible to analyze the results from different types of intervention that might favor nerve regeneration and, consequently, functional recovery 24,25 .…”

Effect of curcumin in mice model of vincristine-induced neuropathy

“…Significant positive correlation between SFI and distal and proximal fiber diameter has been reported earlier (Martins et al, 2006). Thus, SFI provides a non-invasive and quantitative method to evaluate functional recovery of walking ability, the ultimate goal in the regeneration of injured sciatic nerve (Varejao et al, 2004). In the present study, curcumin significantly improved the SFI index which indicates its potential neuroprotective action against vincristine.…”

Evaluation of biodegradable electric conductive tube-guides and mesenchymal stem cells

“…Also, it is considered by the scientific bibliography that rats without sciatic nerve injury withdraw their paws from the hotplate within 4.3 s or less [9,17,31,33] . If there was no paw withdrawal after 12 s, the animal was assigned the maximal WRL of 12 s and the heat stimulus was removed to prevent tissue damage [34][35][36] . For sciatic functional index (SFI), a confined walkway measuring 42 cm long and 8.2 cm wide with a dark shelter at the end (own fabrication) that the rats cross was used.…”

“…In the static sciatic functional index (SSI) is a simpler test where only the parameters TS and ITS are the measurements included in equation (6). Prints for measurements are chosen at the time of walking based on precise, clear and completeness of footprints [9,36,37] . The mean distances of 3 measurements are used to calculate the following factors (dynamic and static):…”