Quantification of Intraepidermal Nerve Fiber Density as a Diagnostic Tool for Neuropathies in Dogs
Abstract
Skin biopsies have been extensively used for the diagnosis of small fiber neuropathies in humans. Although inherited and acquired neuropathies have been documented in dogs, they can be difficult to unequivocally diagnose in the living animal. The use of skin biopsies for the diagnosis of neuropathies in dogs has not been evaluated.
In this thesis, skin biopsies were collected and stained using immunohistochemistry for protein gene product 9.5 (PGP 9.5). Intraepidermal nerve fiber density (IENFD) was quantified using the published guidelines for the diagnosis of peripheral neuropathies in humans.
First, skin biopsies were collected post mortem from adult hound dogs using a 3mm biopsy punch from the skin overlying the larynx. The entire neck was harvested and stored at 4°C for 7 days. Punch biopsies were collected at day 0, day 1, day 2, day 5 and day 7. IENFD was determined for each sample collection day for each dog and compared. A gradual reduction in IENFD was observed over time. Higher mean IENFDs were observed at day 0, day 1 and day 2. There was no significant difference in IENFD between any of the subsequent collection days (p=0.12). These results suggest that refrigeration at 4oC may be acceptable for up to 48 hours after collection, before the samples need to be placed in Zamboni’s fixative.
Then, dogs diagnosed with laryngeal paralysis were recruited to evaluate IENFD in a well-established example of canine neuropathy. Skin biopsies were collected using a 3mm biopsy punch from the skin overlying the larynx. IENFD was determined for these dogs and compared to controls. There was no significant difference between the IENFD of the dogs diagnosed with laryngeal paralysis and the control dogs (p=0.28). These results suggest that it might be difficult to use skin biopsies for diagnosis of peripheral neuropathy in dogs but several modifications of our technique, such as taking samples from the distal hind limb, might be worth considering as means to improve precision of measure of fiber density.
Citation
Hasiuk, Michelle Marguerite Marie (2020). Quantification of Intraepidermal Nerve Fiber Density as a Diagnostic Tool for Neuropathies in Dogs. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /191666.