Curcumin protects against the intestinal ischemia-reperfusion injury: involvement of the tight junction protein ZO-1 and TNF-alpha related mechanism

Present study aimed to investigate the eff ect of curcumin-pretreatment on intestinal I/R injury and on intestinal mucosa barrier. Thirty Wistar rats were randomly divided into: sham, I/R, and curcumin groups (n=10). Animals in curcumin group were pretreated with curcumin by gastric gavage (200 mg/kg) for 2 days before I/R. Small intestine tissues were prepared for Haematoxylin & Eosin (H&E) staining. Serum diamine oxidase (DAO) and tumor necrosis factor (TNF)-alpha levels were measured. Expression of intestinal TNF-alpha and tight junction protein (ZO-1) proteins was detected by Western blot and/or immunohistochemistry. Serum DAO level and serum and intestinal TNF-alpha leves were signifi cantly increased after I/R, and the values were markedly reduced by curcumin pretreatment although still higher than that of sham group (p<0.05 or p<0.001). H&E staining showed the significant injury to intestinal mucosa following I/R, and curcumin pretreatment signifi cantly improved the histological structure of intestinal mucosa. I/R insult also induced significantly down-regulated expression of ZO-1, and the eff ect was dramatically attenuated by curcumin-pretreatment. Curcumin may protect the intestine from I/R injury through restoration of the epithelial structure, promotion of the recovery of intestinal permeability, as well as enhancement of ZO-1 protein expression, and this eff ect may be partly attributed to the TNF-alpha related pathway.

Carcinogenicity and Its Inhibition of 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone, a Tobacco-Specific N-nitrosamine / 环境与健康杂志

The advancement of research work on the carcinogenicity and its inhibition of 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco-specific N-nitrosamine, was reviewed in the present paper. Carbonyl reduction and ?-hydroxylation were the major routes of NNK metabolic activation, the main target organ of NNK carcinogenicity was the lung and the carcinogenic probability related to the individual, organic isothiocyanates were the most potent inhibitors for NNK carcinogenicity. Eating more cruciferae vegetables and fruit and drinking more green and black tea would be helpful for smokers and passive smokers. Research about the nosogenesis and carcinogenicity and its inhibition of the harmful components in cigarette smoke should be further reinforced.