A comparison of diabetic polyneuropathy in type II diabetic BBZDR/Wor rats and in type I diabetic BB/Wor rats.
OBJECTIVE
To examine the functional, metabolic and structural abnormalities in peripheral nerve in the spontaneously Type II (non-insulin-dependent) diabetic BBZDR/Wor rat and compare these data with those in the Type I (insulin-dependent) diabetic BB/Wor rat.


METHODS
Animals were examined at 6 and 14 months of diabetes. Nerve conduction velocity was measured longitudinally. Nerve polyols were analysed using gas liquid chromatography and Na/K(+)-ATPase activity was measured enzymatically. Light and electron microscopic techniques were used for nerve morphometry.


RESULTS
Diabetic BBZDR/Wor rats showed a slowly progressive nerve conduction defect that reached 17% (p < 0.01) at 14 months. There was a decrease in Na+/K(+)-ATPase of 35% (p < 0.05). Structurally, there were mild myelinated fibre atrophy (p < 0.05), mild or absent changes of the node of Ranvier, but significant (p < 0.001) segmental demyelination and Wallerian degeneration. These findings point to a more severe nerve conduction defect, severe myelinated fibre atrophy and profound nodal changes in Type I spontaneously diabetic BB/Wor rats maintained at the same hyperglycaemic concentrations.


CONCLUSIONS
We conclude that other factors, beside hyperglycaemia, are involved in the pathogenesis of the more severe Type I diabetic neuropathy which possibly involve insulin and C-peptide deficiencies.
Sima
A A
AA
Department of Pathology, Wayne State University, Detroit, Michigan 48201, USA.
Zhang
W
W
Xu
G
G
Sugimoto
K
K
Guberski
D
D
Yorek
M A
MA
D000818:Animals; D003433:Crosses, Genetic; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D006614:Hindlimb; D008297:Male; D009046:Motor Neurons / Q000473:pathology / Q000502:physiology; D009413:Nerve Fibers, Myelinated / Q000473:pathology / Q000502:physiology; D009431:Neural Conduction; D011901:Ranvier's Nodes / Q000473:pathology / Q000502:physiology; D051381:Rats; D011913:Rats, Inbred BB; D011919:Rats, Inbred Strains; D012584:Sciatic Nerve / Q000503:physiopathology; D012867:Skin / Q000294:innervation; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis; D013979:Tibial Nerve / Q000503:physiopathology
D000254:Sodium-Potassium-Exchanging ATPase