Effect of Total Flavone of Haw Leaves on Nuclear Factor Erythroid-2 Related Factor and Other Related Factors in Nonalcoholic Steatohepatitis Rats

Objective： To investigate the effect of total flavone of haw leaves（TFHL） on the expression of nuclear factor erythroid-2 related factor（Nrf2） and other related factors in nonalcoholic steatohepatitis（NASH） rats induced by high-fat diet and then to further discuss the mechanism of TFHL＇s prevention against NASH. Methods： High-fat diet was fed to 40 rats to establish the NASH model. Then model rats were intragastrically administrated with 40, 80, 160 mg/（kg·day） TFHL, respectively. The pathological changes of liver tissues in NASH rats were detected by oil red O and hematoxylin-eosin（HE） stainings. The expression of Nrf2 in rat liver was examined through immunohistochemistry. The level of 8-iso-prostaglandin F2α in serum was detected through enzyme linked immunosorbent assay（ELISA）. The mR NA and protein levels of Nrf2 and other related factors in liver tissue were measured by real-time reverse transcriptionpolymerase chain reaction and western blot. Results： Lipid deposition, hepatic steatosis, focal necrosis in lobular inflammation and ballooning degeneration were emerged in livers of NASH rats. The 8-iso-prostaglandin F2α in the serum of NASH rats increased significantly compared with the control group（P〈0.05）. The mR NA of Nrf2, hemeoxyenase1（HO-1） and the mR NA and protein levels of quinine oxidoreductase（NQO1） in NASH rats liver tissue showed a striking increase, while the mR NA levels of Keap1, r-glutamylcysteine synthethase（rG CS） and glutathione S-transferase（GST） were significantly decreased compared with the control group（P〈0.05）. After TFHL treatment, 8-iso-prostaglandin F2α level in serum significantly decreased, and Nrf2 mR NA and protein levels in hepatocytes nucleus enhanced compared with the model group（P〈0.05 or 0.01）. Meanwhile the Keap1 mR NA, the mR NA and protein levels of HO-1, NQO1 antibody, rG CS antibody, GST increased after TFHL treatment（P〈0.05 or 0.01）. Conclusions： Nrf2 and other related factors were involved in development of NASH, and they also served as an important part in its occurrence. By regulating expression of Nrf2 and other related factors, TFHL may play a role in antioxidative stress and prevention of NASH.

Modulation of NRF2 and UGT1A expression by epigallocatechin-3-gallate in colon cancer cells and BALB/c mice

Background Green tea is an important source of flavonoids in human diets and epidemiological data correlate green tea consumption with a reduced cancer risk. Given its complicated properties at effective concentrations, we put epigallocatechin-3-gallate （EGCG） that previously reported on its anti-proliferative activities against several cancer cell lines on our research agenda to further examine the mechanism of its chemopreventive potential. Methods RNA interference （RNAi） expression vector pSilencer 3.1-H1 was used to construct recombinant nuclear factor erythroid 2 related factor 2 （Nrf2）-targeting RNAi plasmids. EGCG （5 μg/ml） was added into the culture fluid of cells before and after transfection. RT-PCR and Western blotting were used to detect the expression of uridine 5＇-diphosphate-glucuronosyltransferase （UGT）IA in cells. Forty male BALB/c mice were assigned to four groups： a normal unexposed control and three groups treated with varying doses of EGCG. Four weeks later, the mice were sacrificed, and their colon tissues were subjected to mRNA and protein expression of Nrf2 and UGT1A via RT-PCR and Western blotting analysis. Results EGCG up-regulated the expression of Nrf2 and increased the level of UGT1A in cells. The blockade of Nrf2 activity via RNA intervention largely attenuated the induction of UGT1A expression by EGCG. In mice, the mRNA and protein levels of Nrf2 and UGT1A detected by RT-PCR and Western blotting increased （both P 〈 0.05 compared with the control）. This increase in Nrf2 expression also had a positive correlation with an increased UGT1A expression. Conclusions EGCG mediated its effect in part by inducing the NRF2 signaling pathway and increasing UGT1A expression. Both in vitro and in vivo studies demonstrated the role of NRF2 and UGT1A expression in the potential use of EGCG as a possible chemopreventive agent and supported further study of EGCG for cancer treatment.