The protective effects of green tea extract against L-arginine toxicity to cultured human mesangial cells.
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.
Shin
Byung Chul
BC
Department of Internal Medicine, Seonam University College of Medicine, Gwangju, Korea.
Ryu
Hyun Ho
HH
Chung
Jong Hoon
JH
Lee
Byoung Rai
BR
Kim
Hyun Lee
HL
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
D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D012333:RNA, Messenger; D013662:Tea; D009569:Nitric Oxide; D001120:Arginine; D052247:Nitric Oxide Synthase Type II