guanosine-triphosphate and thiazolyl-blue

Green tea polyphenols (GTP) are thought to help prevent oxidative stress-related diseases, such as cancer, cardiovascular disease, neurodegenerative disease, and aging. We here investigate the protective mechanisms of GTP on SH-SY5Y cells against apoptosis induced by the pro-parkinsonian neurotoxin 6-hydroxydopamine (6-OHDA). GTP rescued the changes in condensed nuclear and apoptotic bodies, attenuated 6-OHDA-induced early apoptosis, prevented the decrease in mitochondrial membrane potential, and suppressed accumulation of reactive oxygen species (ROS) and of intracellular free Ca(2+). GTP also counteracted the 6-OHDA-induced nitric oxide increase and overexpression of nNOS and iNOS, and decreased the level of protein-bound 3-nitrotyrosine (3-NT). In addition, GTP inhibited the autooxidation of 6-OHDA and scavenged oxygen free radicals in a dose- and time-dependent manner. Our results show that the protective effects of GTP on SH-SY5Y cells are mediated, at least in part, by controlling the ROS-NO pathway.

Topics: Annexin A5; Apoptosis; Blotting, Western; Calcium; Cell Line, Tumor; Cell Survival; Coloring Agents; Dose-Response Relationship, Drug; Flavonoids; Flow Cytometry; Free Radicals; Guanosine Triphosphate; Humans; Membrane Potentials; Mitochondria; Models, Biological; Neurons; Nitric Oxide; Oxidopamine; Oxygen; Parkinson Disease; Phenols; Polyphenols; Quinones; Reactive Oxygen Species; Tea; Tetrazolium Salts; Thiazoles; Time Factors; Tyrosine