Role of green tea polyphenols in noise-induced hearing loss / 中华劳动卫生职业病杂志

Objective@#To investigate the role and mechanism of action of green tea polyphenols in noise-induced hearing loss.@*Methods@#Male specific pathogen-free guinea pigs were randomly divided into normal control group with 9 guinea pigs, noise exposure group with 36 guinea pigs, and green tea polyphenol intervention group with 36 guinea pigs. Auditory brainstem response (ABR) threshold shift was examined before noise exposure and at 1, 3, 7, and 14 days of noise exposure. The surface preparation of cochlear basilar membrane was used for hair cell count and the morphology of hair cells was also observed. Western blot was used to observe the expression of cysteinyl aspartate-specific protease-9 (caspase-9) and cysteinyl aspartate-specific protease-3 (caspase-3) in cochlear tissue.@*Results@#Both the noise exposure group and the green tea polyphenol intervention group had an increase in ABR threshold after noise exposure, and the green tea polyphenol intervention group had a significantly lower ABR threshold shift than the noise exposure group at all time points (P<0.05). Both groups had enlargement, atrophy, or loss of hair cells after noise exposure, and at 7 and 14 days of noise exposure, the noise exposure group had a significantly higher rate of abnormal hair cells than the green tea polyphenol intervention group (P<0.05). Both groups had an increase in the expression of caspase-9 and caspase-3 after noise exposure, and the noise exposure group had a significantly greater increase than the green tea polyphenol intervention group (P<0.05).@*Conclusion@#Green tea polyphenols can reduce noise-induced hearing loss and hair cell injury, possibly by regulating the expression of caspase-9 and caspase-3.

Protective effects of green tea polyphenol against cisplatin-induced nephrotoxicity in rats

OBJECTIVE: This study is to compare the effects of green tea polyphenol (GTP) pre-treatment with those of GTP post-treatment on cisplatin (CP)-induced nephrotoxicity in rat. METHODS: Male Sprague-Dawley rats were randomly divided into six groups. Animals in the control group received 0.9% saline (intraperitoneal); animals in the GTP group received 0.9% saline and GTP (0.2% GTP as their sole source of drinking water); the CP group received only CP (7 mg/kg, intraperitoneal); the CP+preGTP group received GTP from two days before CP to four days after CP and the CP+postGTP group received GTP for four days after CP. CP-induced renal toxicity was evaluated by plasma creatinine and blood urea nitrogen (BUN) concentrations; kidney tissue gamma-glutamyl transpeptidase (GGT) and alkaline phosphatase (AP) activities and histopathological examinations. RESULTS: High serume creatinine and BUN concentrations were observed in CP treated rats. The GGT and AP activites were lower in kidney of CP treated rats compared to control rats. In addition, treatment with CP resulted in development of a marked tubular necrosis, and tubular dilation in kidney of rats. Pretreatment with GTP resulted in markedly reduced elevation of serum creatinine and BUN amounts and changes of GGT and AP activity in kidney induced by CP. CP-induced histopathological changes, including tubular necrosis and dilation, were ameliorated in GTP pre-treated rats, compared to CP alone or GTP post-treated rats. CONCLUSION: These results demonstrate that GTP might have some protective effect against CP-induced nephrotoxicity in rat, and GTP pre-treatment was more effective than GTP post-treatment on reduction of CP-induced renal dysfunction.

The Effect of Green Tea Extract on Cisplatin in Cervical Cancer Cell Lines / 대한산부인과학회지

OBJECTIVE: Green tea polyphenol (GTP) has been shown to have anti-tumor properties in a wide variety of experimental systems. In this study, we evaluated the effects of GTP on the cytotoxic effects of cisplatin in cultured HeLa and SiHa cells. METHODS: The cell lines from Korean Cell Culture Bank were cultured in a RPMI-1640 medium supplemented with a 10% fetal bovine serum, antibiotics streptomycin and penicillin. GTP was extracted from tea leaves (Camellia scinensis) by water extraction and organic solvent fractionation. Cells were seeded at 1 x 10(4) cells/well in RPMI1640 media in triplicate wells on a Nunc Labware 96 well flat bottom microculture plate, with and without GTP (100 microgram/mL) and at different concentrations of cisplatin (0-1000 microgram/mL). After incubating the plates at 37 degrees C in 5% CO2 for 2 days, cell viability was determined using the MTT [3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide; thiazolyl blue] assay. RESULTS: The viability of the HeLa cells was decreased to 14% at a 600 microgram/mL concentration of cisplatin, and to 16% at 600 microgram/mL in the SiHa cells as measured by the MTT assay. However, in the HeLa cell, co-cultured with GTP (100 microgram/mL), the cell viability decreased to 68% at 200 microgram/mL of cisplatin and to 17% at 400 microgram/mL of cisplatin. And in the SiHa cell, co-cultured with GTP (100 microgram/mL), the cell viability decreased to 48% at 200 microgram/mL of cisplatin and to 17% at 400 microgram/mL of cisplatin. CONCLUSION: This study showed that cisplatin with GTP seems to have a potentiating effect on Cisplatin cytotoxicity than cisplatin alone.

The Antiproteinuric Effects of Green Tea Polyphenol on Cyclosporine A-Induced Acute Renal Injury in Mice / 대한신장학회잡지

BACKGROUND:It has been reported that there is association between cyclosporine (CsA) nephrotoxicity and proteinuria. The aim of this study was to investigate the anti-proteinuric effects of green tea polyphenol (GTP) on CsA-induced acute renal injury in mice. METHODS:The mice (n=20) were divided into 4 groups (n=5/group); group 1 (control group) mice were intraperitoneally (IP) injected 0.9% saline, group 2 (CsA group) mice were IP injected CsA 50 mg/kg, group 3 (iNOS inhibitor group) mice were given in addition N(G)-nitro-L-arginine-methyl ester (L-NAME) 12 mmol/L by subcutaneous injection. Group 4 (GTP group) mice were given CsA by IP injection and GTP 100 mg/kg by subcutaneous injection. RESULTS:Urine protein significantly increased in group 2 (28.6+/-11.1 g/kg/day) compared to group 1 (9.1+/-5.5 g/kg/day, p<0.01) and significantly decreased in group 4 (11.2+/-8.8 g/kg/day, p<0.01) compared to group 2. Renal tissue malondialdehyde level of group 2 significantly increased compared to group 1 and significantly decreased in GTP group (p<0.01). CONCLUSION:This study proves that proteinuria of the CsA induced nephrotoxicity is associated with lipid peroxidation and nitric oxide production. GTP treatment has meaningful antiproteinuric effects through antioxidative effect in the kidney from CsA-induced acute renal injury.

Differential Effects of Green Tea Polyphenol in the gamma-irradiation Induced Human Leukemic and Lymphoblastic Cell Damage / 대한핵의학회잡지

PURPOSE: The green tea polyphenol (GTPP) has been known to exert antioxidant activity as a radical scavenger as well as cancer preventive and cancer growth inhibition effect. The aim of this study was to identify whether GTPP not only potentiate the growth inhibition effect in gamma-irradiated human cancer cell but also exert protection action for irradiated human normal cell. MATERIALS AND METHODS: GTPP (80% catechin including > 45% EGCG) added in the HL60, human leukemia, and NC37, human lymphoblast, before irradiation. After establishing the amount of GTPP and the dose of radiation, the cells were treated with the GTPP for 6 hours and irradiated with the determined doses. RESULTS: Viability when 10 mug/ml GTPP added before gamma-irradiation with 1 Gy to NC37 cells was not different in comparison with control but it when was irradiated with 3 Gy significantly different (1 Gy; P=0.126, 3 Gy; P=0.010). 20 mug/ml GTPP did not show significant difference in both NC37 cells irradiated with 1 Gy and 3 Gy (1 Gy; P=0.946, 3 Gy; P=0.096). Viabilities were significantly decreased with concentration of additional GTPP in HL60 with 1 or 3 Gy (1 Gy; 69.0+/-1.7% vs 42.4+/-1.3%, 3 Gy; 66.9+/-3.9% vs 44.2+/-1.6 %). CONCLUSION: In vitro study, we certified that when the cells were irradiated with dose below 3 Gy, GTPP provide not only anticancerous effect against cancer cells but also radioprotective effect in normal cells simultaneously. Theses results suggest the possibility that consumption of green tea could give the radioprotective effect and maximize the effect on internal radiation such as radioiodine therapy concomitantly.