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Distal Degenerative Sensory Neuropathy in a Long-Term Type 2 Diabetes Rat Model

  1. Valentine Brussee1,
  2. GuiFang Guo1,
  3. YingYing Dong1,
  4. Chu Cheng1,
  5. José A. Martinez1,
  6. Darrell Smith23,
  7. Gordon W. Glazner23,
  8. Paul Fernyhough23 and
  9. Douglas W. Zochodne1
  1. 1Department of Clinical Neurosciences and the Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
  2. 2Division of Neurodegenerative Disorders, St. Boniface Hospital Research Centre, Winnipeg, Canada
  3. 3Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Canada
  1. Corresponding author: Dr. D.W. Zochodne, University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta T2N 4N1, Canada. E-mail: dzochodn{at}ucalgary.ca

Abstract

OBJECTIVE—Peripheral neuropathy associated with type 2 diabetes (DPN) is not widely modeled. We describe unique features of DPN in type 2 diabetic Zucker diabetic fatty (ZDF) rats.

RESEARCH DESIGN AND METHODS—We evaluated the structural, electrophysiological, behavioral, and molecular features of DPN in ZDF rats and littermates over 4 months of hyperglycemia. The status of insulin signaling transduction molecules that might be interrupted in type 2 diabetes and selected survival-, stress-, and pain-related molecules was emphasized in dorsal root ganglia (DRG) sensory neurons.

RESULTS—ZDF rats developed slowing of motor sciatic-tibial and sensory sciatic digital conduction velocity and selective mechanical allodynia with preserved thermal algesia. Diabetic sural axons, preserved in number, developed atrophy, but there was loss of large-calibre dermal and small-calibre epidermal axons. In diabetic rats, insulin signal transduction pathways in lumbar DRGs were preserved or had trends toward upregulation: mRNA levels of insulin receptor β-subunit (IRβ), insulin receptor substrate (IRS)-1, and IRS-2. The numbers of neurons expressing IRβ protein were also preserved. There were trends toward early rises of mRNA levels of heat shock protein 27 (HSP27), the α2δ1 calcium channel subunit, and phosphatidylinositol 3-kinase in diabetes. Others were unchanged, including nuclear factor-κB (NF-κB; p50/p105) and receptor for advanced glycosylation endproducts (RAGE) as was the proportion of neurons expressing HSP27, NF-κB, and RAGE protein.

CONCLUSIONS—ZDF type 2 diabetic rats develop a distal degenerative sensory neuropathy accompanied by a selective long-term pain syndrome. Neuronal insulin signal transduction molecules are preserved.

Footnotes

  • Published ahead of print at http://diabetes.diabetesjournals.org on 10 March 2008. DOI: 10.2337/db07-1737.

    The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

    • Accepted February 29, 2008.
    • Received December 12, 2007.
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This Article

  1. Diabetes vol. 57 no. 6 1664-1673
  1. All Versions of this Article:
    1. db07-1737v1
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