Eye wipe test: validation of C-fiber desensitization
This behavorial test evaluates the efficacy of C-fiber desensitization following a capsaicin pre-treatment 4 days prior the eye wipe test.
After an acclimation period, the animal is placed on a 50 x 50-cm table and a single drop of a 100 µg/ml capsaicin solution is instilled into one eye. Then, the animal is observed during a 2-min period, and the eye is extensively rinsed with physiological saline. During the 2-min observation period, the number of defensive wiping movements is counted. C-fibers are considered as desensitized when the defensive wiping movements are almost absent (figure 1).
|Figure 1: Number of eye wipes following the instillation of a single drop of 100 µg/ml capsaicin solution/vehicle in animals from SCI (spinal cord injured) and capsaicin desentized SCI rats (Pelvipharm, internal data).|
- number of defensive wiping movements as an index of C-fiber sensitivity
Links to applicable Targeted disorders / Pathophysiological models