Dihydrolipoic acid protects pancreatic islet cells from inflammatory attack
- 34 Downloads
In vitro models of pancreatic islet cell inflammation are the lysis of isolated islet cells by activated macrophages or by oxygen radicals released by the endothelial enzyme xanthine oxidase. Dihydrolipoic acid protected islet cells in both systems by different modes of action. Macrophage cytotoxicity towards islet cells, which is nitric-oxide-mediated, was suppressed by 2 h of preincubation of macrophages with lipoic acid. Similarly, 2 h of preincubation sufficed to protect islet cells against enzymatically produced oxygen radicals. Dihydrolipoic acid was found by chemiluminescence assay to scavenge directly such radicals. In macrophages dihydrolipoic acid suppressed the production of nitrite as a measure of nitric oxide release. These results suggest that dihydrolipoic acid is an anti-inflammatory agent which at the same time interferes with nitric oxide release from inflammatory macrophages and protects target cells from oxygen radical attack.
KeywordsNitric Oxide Nitrite Xanthine Islet Cell Oxygen Radical
Unable to display preview. Download preview PDF.
- D. N. Granger, M. E. Höllwarth and D. A. Parks,Ischemia reperfusion injury: Role of oxygen-derived free radicals. Acta Phys. Scand.548 (Suppl.), 47–63 (1986).Google Scholar
- Y. J. Suzuki, M. Tsuchiya and L. Packer,Thioctic acid and dihydrolipoic acid are novel antioxidants which interact with reactive oxygen species. Free Rad. Res. Commun.15, 255–263 (1991).Google Scholar
- V. Kagan, S. Khan, C. Swanson, A. Shvedova, E. Serbinova and L. Packer,Antioxidant action of thioctic and dihydrolipoic acid. Free Rad. Biol. Med.9 (Suppl.) 15, (1990).Google Scholar
- T. Mosman,Rapid colorimetric assay for cellular growth and survival: Application to proliferation and cytotoxic assays. J. Immunol. Meth.65, 55–63 (1983).Google Scholar
- F. Denizot and R. Lang,Rapid colorimetric assay for cell growth and survival. Modifications to the tetrazolium dye procedure giving improved sensitivity and reliability. J. Immunol. Meth.89, 271–277 (1986).Google Scholar
- H. Scholich, M. E. Murphy and H. Sies,Antioxidanswirkung von Dihydrolipoat bei der mikrosomalen Lipidperoxidation und ihre Abhängigkeit von α-Tocopherol, in:Neue biochemische, pharmakologische und klinische Erkenntnisse zur Thioctsäure (Eds. H. O. Borbe and H. Ulrich) pp. 124–136, pmi Verlag, Frankfurt 1989.Google Scholar
- J. Barth and H. Scholich,Der Einfluß von DL-α-Liponsäure auf die Chemilumineszenz von Granulozyten und Monozyten in vitro, in:Neue biochemische, pharmakologische und klinische Erkenntnisse zur Thioctsäure (Eds. H. O. Borbe and H. Ulrich) pp. 154–162, pmi Verlag, Frankfurt 1989.Google Scholar