title: Effect of tea polyphenols and tea pigments on the inhibition of precancerous liver lesions in rats.
abstract: The objective of this study was to investigate the inhibitory effect of tea components, tea polyphenols and tea pigments, on precancerous liver lesions in rats. A rat liver precancerous lesion model was established by multiple low-dosage N-nitrosodiethylamine (NDEA) injections, followed by intraperitoneal CCl4 injection and partial hepatectomy (PH). Tea pigments (0.1%) or tea polyphenols (0.1%) were given to Wistar rats in drinking water during the eight weeks of the experiment. The number and area of glutathione S-transferase Pi-positive foci in the rat liver were used as biomarkers of precancerous liver lesions. Western and Northern blot techniques were used to detect rat liver GST-Pi expression at the protein and mRNA levels. At the end of the experiment, tea polyphenols and tea pigments significantly decreased the number and area of GST-Pi-positive foci that were overexpressed in the NDEA-CCl4-PH-treated rats compared with the positive control group. The results also showed that GST-Pi mRNA and protein expression increased significantly in the NDEA-CCl4-PH-treated group, which is consistent with the changing of GST-Pi-positive foci. Tea pigments and tea polyphenols had an inhibitory effect on the overexpression of GST-Pi mRNA and protein in NDEA-CCl4-PH-treated rats. These results suggest that tea pigments and tea polyphenols are effective in preventing the occurrence and progression of precancerous liver lesions in rats.
authors.affiliation: Institute of Nutrition and Food Hygiene, Chinese Academy of Preventive Medicine, Beijing 100050, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Gong
authors.forename: C
authors.initials: C
authors.lastname: Han
authors.forename: J
authors.initials: J
authors.lastname: Chen
mesh_terms: D000818:Animals; D015415:Biomarkers; D015152:Blotting, Northern; D015153:Blotting, Western; D004195:Disease Models, Animal; D004326:Drinking; D005419:Flavonoids; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008114:Liver Neoplasms, Experimental / Q000517:prevention & control*; D008297:Male; D010636:Phenols / Q000008:administration & dosage / Q000494:pharmacology*; D010860:Pigments, Biological / Q000008:administration & dosage / Q000494:pharmacology*; D011108:Polymers / Q000008:administration & dosage / Q000494:pharmacology*; D059808:Polyphenols; D011230:Precancerous Conditions / Q000517:prevention & control*; D012333:RNA, Messenger / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D013662:Tea / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D005419:Flavonoids; D010636:Phenols; D010860:Pigments, Biological; D011108:Polymers; D059808:Polyphenols; D012333:RNA, Messenger; D013662:Tea; D005982:Glutathione Transferase