title: [Effects of tea polyphenols on the activity of GSH-Px and NOS, and the content of MDA and NO in rats fed with high methionine diet].
abstract: OBJECTIVE
  To study the effect of tea polyphenols (TP) on the content of malondialdehyde (MDA) and nitric oxide (NO) and the activity of GSH-Px and nitric oxide synthase (NOS) in rats fed with high methionine diet.
  
  
  METHODS
  Wistar rats were randomly divided into 5 groups: model group, control group and 3 TP groups. Rats in model group and TP groups were fed with 3% methionine in diet, and rats in control group with routine diet. Rats in low-, midium- and high-dose TP groups were treated with 50, 100 and 200 mg/kg TP respectively by gavage every day for 8 weeks. Rats in control group and model group were given equal volume of distilled water. Activities of GSH-Px and NOS and contents of NO and MDA in serum were detected. Histopathological changes of aortic arc were observed by hematoxylin-eosin (HE) staining techniques.
  
  
  RESULTS
  There were no statistically significant changes of GSH-Px activities among all groups. Compared with model group, MDA contents decreased by 27.1% in low-dose TP group (P < 0.01). Activities of NOS in TP groups increased respectively by 18.7%, 15.1% and 18.0% (P < 0.01), and NO contents in low- and high-dose TP groups increased by 113.4% and 73.4% (P < 0.01), respectively. A proliferation of vascular smooth muscle cells (VSMC) and increased thickness of aortic arch was observed in rats of model group, and these changes were suppressed in TP groups.
  
  
  CONCLUSIONS
  Lipid peroxidation induced by high-methionine diet could be protected by TP. The function of endothelial cells could be maintained by increasing the NOS activity and NO contents, thus the injury of endothelial cells induced by high-methionine diet could be prevented and reduced by TP.
authors.affiliation: Wuxi Maternal and Child Health Hospital, Wuxi 214002, China. pjj2226@yahoo.cn
authors.forename: Jingjing
authors.initials: J
authors.lastname: Pei
authors.forename: Shuai
authors.initials: S
authors.lastname: Guo
authors.forename: Cuili
authors.initials: C
authors.lastname: Zhang
authors.forename: Zhenping
authors.initials: Z
authors.lastname: Zhu
authors.forename: Lihua
authors.initials: L
authors.lastname: Yu
authors.forename: Keqin
authors.initials: K
authors.lastname: Xie
authors.forename: Xiulan
authors.initials: X
authors.lastname: Zhao
mesh_terms: D000818:Animals; D004032:Diet; D005979:Glutathione Peroxidase / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008715:Methionine / Q000008:administration & dosage / Q000009:adverse effects*; D009569:Nitric Oxide / Q000097:blood*; D019001:Nitric Oxide Synthase / Q000097:blood*; D059808:Polyphenols / Q000302:isolation & purification / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013662:Tea / Q000737:chemistry*
chemical_list: D059808:Polyphenols; D013662:Tea; D009569:Nitric Oxide; D008315:Malondialdehyde; D008715:Methionine; D005979:Glutathione Peroxidase; D019001:Nitric Oxide Synthase