Comparison between electrophysiologic and morphologic changes in lead induced peripheral neuropathy in rats

Abstract

Compound nerve action potential (CNAP) of the mixed peripheral nerve is composed of A alpha beta, A delta, and C potentials. All components of CNAPs in the sciatic nerve were recorded by stimulating the tibial nerve of both control and lead-poisoned rats. Marked decrease of nerve conduction velocity and prolonged duration were found in A alpha beta and A delta fibers especially in large myelinated A alpha beta fibers. The amplitude decreased in A alpha beta potential, but the area did not change. In C potential produced by activation of unmyelinated fibers, nerve conduction velocity slightly decreased, but the amplitude and area did not significantly change. Pathologic correlates revealed prominent segmental demyelination with significant decrease of large myelinated fiber densities. Minimal axonal degeneration of unmyelinated fibers was present. We can conclude that electrophysiologic changes in the lead-poisoned rats correlate with pathologic changes in them.

CHAPTER 11. Lead

“…Despite these deficiencies, studies in animal models have confirmed the neurotoxicity and nephrotoxicity of lead and its capacity to disturb iron and copper metabolism in haemopoiesis and calcium, zinc and magnesium in epithelial cell differentiation. 42,[59][60][61][62][63][64][65] Experimental evidence is available also to show that lead intoxication is associated with osteological abnormality and defects in mineralisation through inhibition of alkaline phosphatase and other key enzymes involved in calcium metabolism. 66,67 Experimental studies in rodents provide strong evidence that certain lead compounds should be considered carcinogenic following oral or in-diet administration, and through parenteral administration.…”