p75 Neurotrophin receptor induction and macrophage infiltration in peripheral nerve during experimental diabetic neuropathy: Possible relevance on regeneration

Giancarlo Conti, Guido Stoll, Elio Scarpini, Pier Luigi Baron, Roberto Bianchi, Simona Livraghi, Guglielmo Scarlato

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Abstract

In this study we examined the expression of the neurotrophin receptor p75 (p75NTR) and the activation of macrophages in the sciatic nerve of rats at different time points after the induction of diabetes with streptozotocin (STZ). Northern blot and immunocytochemical analysis showed that p75NTR was not detectable in the sciatic nerve by Week 2 after STZ treatment. At this time, single nerve fiber immunostaining using ED1 monoclonal antibody revealed that active macrophages were infiltrating the endoneurium, which had a normal morphological aspect. By Weeks 5 and 15 p75NTR mRNA and protein were induced in the endoneurium of diabetic animals. Immunocytochemical analysis of teased single nerve fibers showed that p75NTR protein was distributed uniformly along isolated fibers with no pathological evidence of axonal degeneration or myelin disruption. At this time, cells of the phagocyte lineage had already disappeared from the nerve. These data show that during experimental diabetic neuropathy, the endoneurial induction of p75NTR is localized along isolated nerve fibers showing no morphological alterations, and in time, follows the recruitment of active macrophages in the nerve, suggesting that these cells, directly or through their products, can influence p75NTR induction. This process might play an important role in STZ diabetic neuropathy, as a response to decreased levels of neurotrophins such as NGF and promoting nerve regeneration in the early phases of the disease.

Original languageEnglish
Pages (from-to)206-211
Number of pages6
JournalExperimental Neurology
Volume146
Issue number1
DOIs
Publication statusPublished - Jul 1997

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ASJC Scopus subject areas

  • Neurology
  • Neuroscience(all)

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