Compression of The Sciatic Nerve May not Contribute to Ipsilateral Hyperalgesia Development in Ovariectomized Female Rats!

von Frey Filament (vFF) is an aesthesiometer to measure paw withdrawal thresholds. Our aim was to validate the manually von Frey test technique for assessing neuropathic pain behavioral signs in a sciatic nerve ligation model.

In this experimental study, peripheral neuropathic pain associated with sciatic nerve chronic ligation (SN-CL) was induced. Filaments used against posterior pad mid-plantar region using a simplified up-down method (SUDO). In addition to baseline withdrawal thresholds, the behavioral test was repeated after surgery thrice more with an interval of ten days. vFF (2 to 26 g) were used in ascending order for hyperalgesia assessment.

In SN-CL rats, the results validate a loss of pain sensation, resulted in, long-lasting ipsilateral allodynia with the development of contralateral allodynia later and an extraterritorial development of neuropathic signs. Variability for the development of ipsilateral and contralateral allodynia over time was noted in sham (SH) control rats. SN-CL group showed a contralateral hyperalgesia development just at the 16th-day after surgery with an absence of ipsilateral hyperalgesia development at the different days of paw withdrawal thresholds measurements.

Manually vFF test technique was successfully used for assessing neuropathic pain behavioral signs in sciatic a nerve ligation model with the absence of ipsilateral hyperalgesia development.