noc-5 and linsidomine

We utilized fetal spinal motor neurons isolated from either NFL (-/-) or hNFL (+/+) transgenic mice to determine whether the loss of the low molecular weight neurofilament protein (NFL) places spinal motor neurons at a greater risk for cell death triggered by reactive nitrating species (RNS). After 21 days in serum-free, antibiotic-free medium, both the NFL (-/-) and hNFL (+/+) motor neurons developed neurofilamentous aggregates. Cultures were then exposed to nitric oxide(100 microM NOC 5, 100 microM NOC 12, or 2 mM sodium nitroprusside) or to peroxynitrite (250 mM SIN-1) forvarying intervals. NFL (-/-) cultures demonstrated extensive numbers of apoptotic neurons within six hours and complete cell loss by 24 hours in response to NOC 5 and NOC 12. In contrast, apoptosis was only observed in the motor neurons derived from control (C57bl/6) or hNLF (+/+) mice at 24 hours. In response to 2 mM sodium nitroprusside, necrosis was induced in all cells within 60 minutes. In response to 250 mM SIN-1, both C57bl/6 and hNFL (+/+) cells survived to six hours with only minimal evidence of degeneration while NFL (-/-) motor neurons were necrotic by 60 minutes. These observations suggest that NFL deficient motor neurons are at an enhanced risk of cell death mediated by RNS.

Topics: Animals; Cell Death; Cells, Cultured; Humans; In Vitro Techniques; Mice; Mice, Inbred C57BL; Mice, Transgenic; Molsidomine; Motor Neurons; Neurofilament Proteins; Nitric Oxide; Nitric Oxide Donors; Nitroprusside; Nitroso Compounds; Peroxynitrous Acid; Spinal Cord; Superoxide Dismutase; Triazenes

Chondrocyte cell death, possibly related to increased production of endogenous nitric oxide (NO), has been observed during the pathogenesis of osteoarthritis and rheumatoid arthritis. The purpose of this study was to investigate the potential role of NO in causing chondrocyte cell death and to determine the contribution of other reactive oxygen species (ROS).. Cell death and cytotoxicity were evaluated in human articular chondrocytes in response to various NO donor compounds with and without agents that stimulate or inhibit the production of additional ROS using both the alginate bead and the monolayer culture systems. Cell death was quantified by a total cell count with fluorescent labels, and cytotoxicity was measured as a function of cellular NADH- and NADPH-dependent dehydrogenase activity. To determine if the redox status of the chondrocyte could influence the observed effect of NO, cells were preincubated for 24 hours in L-cystine- and glutathione (GSH)-depleted media to reduce intracellular GSH levels, a major defense mechanism against oxidative stress. Apoptosis was analyzed with the quantification of histone-associated DNA fragments.. Treatment of chondrocytes with peroxynitrite (ONOO-), 3-morpholinosydnonimine (SIN-1), and sodium nitroprusside (SNP) resulted in apoptotic cell death at concentrations of 0.5 mM, 1.0 mM, and 0.5 mM, respectively. In contrast, treatment of chondrocytes with diazeniumdiolates (or the "NOC" compounds, NOC-5 and NOC-12) at concentrations as high as 2.0 mM did not cause cell death. Furthermore, NOC-5 and NOC-12, at all concentrations tested (0.125-2.0 mM), could prevent cell death caused by oxidative stress. Selective ROS scavengers protected against cell death caused by either SIN-1 or ONOO-; however, no protection could be afforded against the cytotoxicity of SNP with any of the ROS scavengers tested.. These results show that NO by itself is not cytotoxic to cultured chondrocytes and can even be protective under certain conditions of oxidative stress. Chondrocyte cell death from NO occurs under conditions where other ROS are also generated.

Topics: Alginates; Apoptosis; Cell Survival; Cells, Cultured; Chondrocytes; Humans; Microspheres; Molsidomine; NAD; NADP; Nitrates; Nitric Oxide; Nitric Oxide Donors; Nitrites; Nitroprusside; Nitroso Compounds; Oxidative Stress; Reactive Oxygen Species; Triazenes