title: The protective effects of green tea extract against L-arginine toxicity to cultured human mesangial cells.
abstract: The aim of this study was to investigate whether green tea extract (GTE) has the protective effects on excess L-arginine induced toxicity in human mesangial cell. Human mesangial cells treated with L-arginine were cultured on Dulbecco's modified eagle medium in the presence and absence of inducible nitric oxide synthase (iNOS) inhibitor and GTE. The cell proliferation was determined by 3 (4,5-dimethylthiazol-2-yl)-2, 5-diphengltetrqzolium bromide, a tetrazole assay. The iNOS mRNA and its protein expression were detected by reverse transcription polymerase chain reaction and Western blot, respectively. The concentration of nitric oxide (NO) was measured by NO enzyme-linced immuno sorbent assay kit. L-arginine significantly inhibited the proliferation of human mesangial cells, and induced the secretion of NO to the media. NO production by L-arginine was significantly suppressed by GTE and iNOS inhibitor (p<0.01). The expression level of iNOS mRNA and its protein that was significantly increased by L-arginine was decreased by iNOS inhibitor but not by GTE. GTE protected the mesangial cells from the NO-mediated cytotoxicity by scavenging the NO rather than by iNOS gene expression. Therefore, we conclude that GTE has some protective effect for renal cells against oxidative injury possibly by polyphenols contained in GTE.
authors.affiliation: Department of Internal Medicine, Seonam University College of Medicine, Gwangju, Korea.
authors.forename: Byung Chul
authors.initials: BC
authors.lastname: Shin
authors.forename: Hyun Ho
authors.initials: HH
authors.lastname: Ryu
authors.forename: Jong Hoon
authors.initials: JH
authors.lastname: Chung
authors.forename: Byoung Rai
authors.initials: BR
authors.lastname: Lee
authors.forename: Hyun Lee
authors.initials: HL
authors.lastname: Kim
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001120:Arginine / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity*; D002460:Cell Line; D049109:Cell Proliferation; D002470:Cell Survival; D005419:Flavonoids / Q000378:metabolism; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism; D006801:Humans; D050527:Mesangial Cells / Q000166:cytology* / Q000378:metabolism; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D059808:Polyphenols; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013662:Tea
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D012333:RNA, Messenger; D013662:Tea; D009569:Nitric Oxide; D001120:Arginine; D052247:Nitric Oxide Synthase Type II