Effect of chronic autoimmune nerve growth factor deprivation on sympathetic neuroaxonal dystrophy in rats

Nerve growth factor (NGF) deficiency has been proposed as a possible pathogenetic mechanism underlying the sympathetic autonomic neuropathy which develops in clinical and experimental diabetes and aging. To determine if long-term NGF deficiency alone would reproduce the distinctive sympathetic neuropathology of streptozocin-induced diabetes or aging in rats, nondiabetic animals were deprived of NGF for 12 months using an autoimmune paradigm. Neuroaxonal dystrophy (NAD), the neuropathologic hallmark of experimental sympathetic diabetic neuropathy and aging, was not increased in frequency in prevertebral superior mesenteric or paravertebral superior cervical ganglia in comparison to age-matched controls. Residual neurons in chronically NGF deprived sympathetic ganglia did not show significant atrophy, chromatolysis, active neuronal degeneration or intraganglionic debris. Postganglionic noradrenergic axons in ileal mesenteric nerves also failed to develop NAD in chronic autoimmune NGF-deprived rats as they would have in animals diabetic for the same duration. These results suggest that simple, isolated NGF deficiency maintained for long periods of time in nondiabetic animals is not sufficient to produce NAD in the pattern of experimental rat diabetes and aging.