Green tea polyphenols attenuate hepatic steatosis, and reduce insulin resistance and inflammation in high-fat diet-induced rats.

Non­alcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis, insulin resistance and inflammation; however, the exact pathogenesis of NAFLD is not fully understood. Green tea polyphenols (GTP) exhibit beneficial effects against metabolic syndrome. However, the effect of GTP on NAFLD remains largely unknown. The aim of the present study was to investigate the effects of GTP on NAFLD in high­fat diet (HFD)­induced rats. The NAFLD rat model was induced with a HFD for 8 weeks. A total of 30 adult male Sprague Dawley rats were randomly divided into three groups: i) Normal control group; ii) HFD group; and iii) HFD with GTP group. Hematoxylin and eosin and Oil Red O analyses were performed. The levels of alanine aminotransferase (ALT), aspartate amino-transferase (AST) and inflammatory cytokines in the serum, as well as oxidative stress markers and hepatic lipids in the liver were measured. In addition, parameters associated with glucose metabolism were also assessed. Western blotting and RT­qPCR were used to determine the expression levels of 5' adenosine monophosphate­activated protein kinase (AMPK). HFD­induced rats exhibited features associated with NAFLD. GTP intervention significantly reduced serum ALT and AST levels. Fasting serum glucose, insulin resistance and hepatic lipid levels were all decreased in the GTP­treated rats. GTP also significantly decreased the levels of TNF­α, IL­6 and malondialdehyde. In contrast, superoxide dismutase levels were increased in the liver. Furthermore, GTP also significantly increased phosphorylation of AMPK and attenuated histopathological changes indicative of injury in liver tissue. GTP has a protective effect on HFD­induced hepatic steatosis, insulin resistance and inflammation, and the underlying mechanism may involve the AMPK pathway.

The effect of treatment with α-glycosidases from Bacteroides fragilis on the survival of rat erythrocytes in the circulation.

BACKGROUND: It has been demonstrated recently that α1,3-galactosidase from Bacteroides fragilis can efficiently convert human group B red blood cells (RBC) to group O cells. In addition, in vitro data indicated that the enzymatic conversion process did not affect the physiological or metabolic parameters of the RBC. The aim of this study was to investigate the lifespan of enzyme- treated RBC in vivo in the circulation. MATERIALS AND METHODS: This was an experimental, randomised study. The rat was selected as the experimental subject because it expresses α-1,3galactosyl on its RBC. The efficiency of Galα1,3Gal epitope removal from RBC treated with α1,3-galactosidase was tested before the transfusion experiment to track the survival of RBC in the circulation. The animals were divided into three groups and injected via the tail vein with native, mock-treated or enzyme-treated RBC labelled with fluorescein isothiocyanate. The survival rates of the fluorescently labelled RBC were monitored by flow cytometry. RESULTS: Flow cytometry showed that α-galactosidase (0.02 mg/mL for RBC with a haematocrit of 30%) efficiently removed Galα1,3Gal epitopes from rat erythrocytes, although small amounts of remaining Galα1,3Gal epitopes were still detected. The in vivo data demonstrated that the half-life of enzyme-treated RBC was a little shorter than that of native RBC. However, the 24-hour survival fractions of native, mock-treated and enzyme-treated RBC were virtually identical. Most importantly, the enzyme-treated RBC, like the native RBC, were still detectable 35 days after transfusion. DISCUSSION: Our results indicate that α-glycosidase treatment had little effect on the in vivo survival kinetics of RBC. These data add further support to the feasibility of translating enzymatic conversion technology into clinical practice.

Effect of antiallergic herbal agents on chloride channel-3 and immune microenvironment in nasal mucosal epithelia of allergic rhinitis rabbits.

BACKGROUND: Allergic rhinitis (AR) is a Th2 dominant cytokine response. Chloride channel-3 (ClC-3) plays an important role in nasal mucosal edema and inflammatory pathologic changes in AR. Antiallergic herbal agents (AHA) are antiallergic herbal products. In the previous study, we have demonstrated that AHA clearly inhibited allergic medium and relieved allergic reaction of AR. The aim of this study was to evaluate the function of ClC-3 and discuss the possible therapeutic effects of AHA on immune microenvironment in AR. METHODS: AHA were produced and used to treat AR. An animal model of an AR rabbit was established by ovalbumin (OVA). The rhinitis rabbits were randomly divided into three groups: AHA treated group (AHATG), model group (MG) and healthy control group (HCG). The expressions of ClC-3 protein were examined by immunohistochemical method. The mucosal epithelial cells of all the rabbit groups were primarily cultured with tissue culture method in vitro with or without rhIL-4 or rhIL-2. Furthermore, the expressions of ClC-3 mRNA were detected by real-time PCR. The levels of monocyte chemotactic factor-1 (MCP-1) and vascular cell adhesion molecule-1 (VCAM-1) protein in culture supernatants were measured by ELISA. RESULTS: The expressions of ClC-3 mRNA increased more in mucosal epithelial cells of MG than those in AHATG and HCG (P < 0.01). The levels of ClC-3 mRNA, MCP-1 and VCAM-1 protein in culture supernatants of MG were significantly higher than those in the other two groups (P < 0.01). Those were significantly increased in MG untreated 12 hours later than those in other two groups (P < 0.01). The expressions of ClC-3 mRNA, MCP-1 and VCAM-1 protein in culture supernatants of MG and HCG treated with rhIL-4 were significantly higher than those in the AHATG treated with rhIL-4 (P < 0.01). The levels of ClC-3 mRNA, MCP-1 and VCAM-1 protein in culture supernatants of all groups treated with rhIL-2 showed no significant changes (P > 0.05). CONCLUSIONS: AHA can inhibit the secretions of ClC-3, MCP-1 and VCAM-1 in mucosal epithelia and improve inflammatory reaction of AR. ClC-3 plays an important role in the secretion of cytokines and mucosal inflammatory response in AR. RhIL-4 can enhance the secretion of ClC-3, MCP-1 and VCAM-1 in mucosal epithelial cells, especially during the AR process. These enhanced effects of rhIL-4 were significantly suppressed by AHA. The secretions of ClC-3, MCP-1 and VCAM-1 can not be induced obviously by rhIL-2 in mucosal epithelial cells in AR.

B to O erythrocyte conversion by the recombinant alpha-galactosidase.

BACKGROUND: Human group O red blood cells have great benefit in specialized transfusion areas such as armed conflict and natural calamity. The group B antigen differs structurally from group O antigen only by the addition of one terminal alpha-linked galactose residue. In this study we aimed to remove the terminal galactose from group B red blood cell to get group O red blood cell. METHODS: alpha-galactosidase cDNA was cloned by RT-PCR from Catimor coffee beans grown on Hainan Island of China. The vector for alpha-galactosidase cDNA expression was constructed and transferred into Pichia pastoris cells by electroporation. The transgenic cells were cloned by fermentation and the recombinant alpha-galactosidase was purified by ion exchange chromatography. After studying the biochemical characters of alpha-galactosidase, we have used it in converting human erythrocytes from group B to group O. RESULTS: The purity of recombinant alpha-galactosidase was higher than 96%, which was thought to be suitable for the use of blood conversion. Enzymatically converted human group O red blood cells (ECHORBC) exhibited membrane integrity, metabolic integrity, normal cell deformation and morphology. There were no coagulation between ECHORBC and any group of human blood. The ECHORBC will keep normal structure and function for a period of 21 days at 4 degrees C in monoammoniumphosphate nutrient solution. Experiments with Rhesus monkeys and gibbons showed that transfusion of enzymatically converted erythrocytes was safe. CONCLUSION: ECHORBC can be easily obtained from group B red blood cell by alpha-galactosidase digestion. This study suggests that ECHORBC could be transfused to patients safely and efficiently.