The Protective Effects of Green Tea Extract against L-arginine Toxicity to Cultured Human Mesangial Cells

다국어 초록 (Multilingual 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.

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