Intraepidermal nerve fiber density in rat foot pad: neuropathologic-neurophysiol

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J Peripher Nerv Syst. 2005 Jun;10(2):202-8.

Intraepidermal nerve fiber density in rat foot pad: neuropathologic-

neurophysiologic correlation.

Lauria G, Lombardi R, Borgna M, Penza P, Bianchi R, Savino C, Canta

A, Nicolini G, Marmiroli P, Cavaletti G.

Immunology and Muscular Pathology Unit, National Neurological

Institute " Carlo Besta " , Milan, Italy.

Quantification of cutaneous innervation in rat footpad is a useful

tool to investigate sensory small-diameter nerve fibers, which are

affected early in peripheral neuropathies. The aim of this work was

to provide normative reference data on the density of intraepidermal

nerve fibers (IENFs) and Langerhans cells in the hindpaw footpad of

Sprague-Dawley and Wistar rats. We also evaluated the sensibility of

IENF density by comparing neuropathologic findings with

neurophysiologic examination and the presence of peripheral

neuropathy in two well-characterized animal models of neuropathy.

IENF density was quantified in 22 Sprague-Dawley rats and 13 Wistar

rats and compared with 19 age-matched Sprague-Dawley rats with

streptozotocin-induced diabetic neuropathy and 30 age-matched Wistar

rats with cisplatin- or paclitaxel-induced neuropathy. Antidromic

tail sensory nerve conduction velocity (SNCV) was assessed in all

animals. IENF and Langerhans cell densities were constant in healthy

Sprague-Dawley rats at any age, and they were similar to those

observed in healthy Wistar rats. In neuropathic rats, both SNCV and

IENF density were significantly reduced with respect to controls.

Quantification of IENF density was significantly correlated with

changes in conduction velocity. Diabetic neuropathy rats alone showed

a significantly higher density of Langerhans cells compared with

controls. Our study demonstrated that IENF density quantification

correlates with SNCV changes and suggests that this might represent a

useful outcome measurement in experimental neuropathies.