Oxidative-nitrosative stress and poly(ADP-ribose) polymerase (PARP) activation in experimental diabetic neuropathy: the relation is revisited.
Poly(ADP-ribose) polymerase (PARP) activation, an important factor in the pathogenesis of diabetes complications, is considered a downstream effector of oxidative-nitrosative stress. However, some recent findings suggest that it is not necessarily the case and that PARP activation may precede and contribute to free radical and oxidant-induced injury. This study evaluated the effect of PARP inhibition on oxidative-nitrosative stress in diabetic peripheral nerve, vasa nervorum, aorta, and high glucose-exposed human Schwann cells. In vivo experiments were performed in control rats and streptozocin (STZ)-induced diabetic rats treated with and without the PARP inhibitor 3-aminobenzamide (ABA) (30 mg . kg(-1) . day(-1) i.p. for 2 weeks after 2 weeks of untreated diabetes). Human Schwann cells (HSC) (passages 7-10; ScienCell Research Labs) were cultured in 5.5 or 30 mmol/l glucose with and without 5 mmol/l ABA. Diabetes-induced increase in peripheral nerve nitrotyrosine immunoreactivity, epineurial vessel superoxide and nitrotyrosine immunoreactivities, and aortic superoxide production was reduced by ABA. PARP-1 (Western blot analysis) was abundantly expressed in HSC, and its expression was not affected by high glucose or ABA treatment. High-glucose-induced superoxide production and overexpression of nitrosylated and poly(ADP-ribosyl)ated protein, chemically reduced amino acid-(4)-hydroxynonenal adducts, and inducible nitric oxide synthase were decreased by ABA. We concluded that PARP activation contributes to superoxide anion radical and peroxynitrite formation in peripheral nerve, vasa nervorum, and aorta of STZ-induced diabetic rats and high- glucose-exposed HSC. The relations between oxidative-nitrosative stress and PARP activation in diabetes are bi- rather than unidirectional, and PARP activation cannot only result from but also lead to free radical and oxidant generation.
Obrosova
Irina G
IG
Pennington Biomedical Research Center, Louisiana State University System, 6400 Perkins Rd., Baton Rouge, Louisiana 70808, USA. obrosoig@pbrc.edu
Drel
Viktor R
VR
Pacher
Pal
P
Ilnytska
Olga
O
Wang
Zhong Q
ZQ
Stevens
Martin J
MJ
Yorek
Mark A
MA
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology*; D004789:Enzyme Activation; D008297:Male; D018384:Oxidative Stress / Q000502:physiology*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D011065:Poly(ADP-ribose) Polymerases