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The employment of transgenic mouse models for peripheral nerve regeneration studies is continuously increasing. In this paper, we describe a standardized method for inducing a crush lesion in mouse median nerve using a non-serrated clamp exerting a crush compression force of 20.43 MPa for a duration of 30 s. Quantitative assessment of posttraumatic functional recovery by grasping test showed that recovery was very fast and mice returned to baseline performance already after 20 days only. Stereological analysis of nerve fibers distal to the crush lesion showed the presence of axons with a significantly smaller size and thinner myelin sheath in comparison to controls. This experimental nerve injury model is highly reproducible and the impact on animal well-being is minimal. Its employment can be particularly indicated for exploring the basic neurobiological mechanisms of peripheral nerve regeneration.

The experimental model of choice for many peripheral nerve investigators is the rat. Walking track analysis is a useful tool in the evaluation of functional peripheral nerve recovery in the rat. This quantitative method of analyzing hind limbs performance by examining footprints, known as the sciatic function index (SFI), has been widely used to quantify functional recovery from sciatic nerve injury in a number of different injury models, although some limitations of the SFI has been questioned by several authors. This article is designed to offer the peripheral nerve investigator a noninvasive method to evaluate quantitatively the integrated motor recovery in experimental studies.

We have recently described the sequence of functional and morphologic changes occurring after a standardized sciatic nerve crush injury. An 8-week post-injury time was used because this end point is the far most used. Unexpectedly, both functional and morphological data revealed that animals had still not recovered to normal pre-injury levels. Therefore, the present study was designed in order to prolong the observation up to 12 weeks. Functional recovery was evaluated using sciatic functional index (SFI), static sciatic index (SSI), extensor postural thrust (EPT), withdrawal reflex latency (WRL) and ankle kinematics. In addition, quantitative morphology was carried out on regenerated nerve fibers. A full functional recovery was predicted by SFI/SSI, EPT and WRL but not all ankle kinematics parameters. Moreover, only two morphological parameters (myelin thickness/axon diameter ratio and fiber/axon diameter ratio) returned to normal values. Data presented in this paper provide a baseline for selecting the adequate end-point and methods of recovery assessment for a rat sciatic nerve crush study and suggest that the combined use of functional and morphological analysis should be recommended in this experimental model.

In rat gait kinematics, the method most frequently used for measuring hindlimb movement involves placing markers on the skin surface overlying the joints being analyzed. Soft tissue movement around the knee joint has been considered the principle source of error when estimating hindlimb joint kinematics in rodents. However, the motion of knee marker was never quantified, nor the different variations in joint angle associated with this gait analysis system. The purpose of this study was two-fold. The first purpose was to expand upon the limited pool of information describing the effect of soft tissue movement over the knee upon the angular positions of the hip, knee and ankle of rats during treadmill locomotion. Secondly, it was a goal of this study to document the magnitude of the skin displacement when using markers that were attached superficially to the knee joint. This was examined by comparing the hindlimb kinematics in sagittal plane during treadmill locomotion determined from the marker attached to the knee and when the knee position was determined indirectly by computer analysis. Results showed that there is a considerable skin movement artefact which propagates to knee joint position and hindlimb kinematics estimates. It was concluded that these large errors can decrease data reliability in the research of rat gait analysis.