Protective effects of γ-irradiated Astragalus polysaccharides on intestinal development and mucosal immune function of immunosuppressed broilers.

This study was aimed to assess the protective effects of γ-irradiated Astragalus polysaccharides (IAPS) on the development of small intestine and intestinal mucosal immunity of immunosuppressed broilers induced by cyclophosphamide (CPM). A total of 384 one-day-old broiler chicks with similar initial weight were randomly assigned into 6 groups: non-treated group (control), and CPM-treated groups fed either a basal diet or the diets containing 900 mg/kg APS, or 900, 600, 300 mg/kg IAPS, respectively. On days 16, 18, and 20, all broilers except for control group were intramuscularly injected with 0.5 mL CPM (40 mg/kg of BW). Broilers in the control group were intramuscularly injected with 0.5 mL sterilized saline (0.75%, wt/vol). This trial was lasted for 21 d. The results revealed that both APS and IAPS treatment elevated the duodenal IgA-producing cells number and the jejunal mRNA expression of interleukin-2 (IL-2), interleukin-10 (IL-10), and interferon γ of CPM-injected broilers (P < 0.05). The decreased jejunal villus height (VH), the ratio of VH to crypt depth (V/C), as well as the intestinal intraepithelial lymphocytes (IELs) and goblet cells number in CPM-injected broilers were elevated by dietary supplementation with 900 mg/kg APS or 900, 600 mg/kg IAPS (P < 0.05). The CPM-induced decrease in jejunum index, the duodenal VH and the jejunal IgA-producing cells number were only improved in the 900 mg/kg IAPS group (P < 0.05). Furthermore, the number of IELs and IgA-producing cells in duodenum, VH, V/C, the number of goblet cells, and mRNA expression of IL-2 and IL-10 in jejunum were higher in the 900 mg/kg IAPS group than those in the 900 mg/kg APS group (P < 0.05). In summary, IAPS possessed stronger immunomodulatory effect than APS at the same supplementation level. Therefore, gamma irradiation can be used as an alternative treatment to enhance the immunomodulatory activity of APS.

The mechanism of COX-2 regulating HERG channel in gastric cancer cells.

OBJECTIVES: To elucidate the signal transduction pathway, by which cyclooxygenase-2 (COX-2) regulates human erg-related gene (HERG) current in gastric cancer cells. METHODS: The HERG mRNA, protein and current in gastric cancer cells transfected with or without COX-2 antisense vector were measured by RT-PCR, Western blot and patch-clamp, respectively. Cyclic adenosine monophosphate (cAMP) concentration in gastric cancer cells transfected with or without COX-2 antisense vector was measured by ELISA. RESULTS: Transfection with COX-2 antisense vector did not alter the expression of HERG mRNA and protein, but it diminished the amplitude of HERG current in gastric cancer cells (p < 0.05). The cAMP concentration in gastric cancer cells transfected with COX-2 antisense vector was lower than that in parental gastric cancer cells (p < 0.05). COX-2 inhibitor and PGE2 had influence on the HERG current in gastric cancer cells. COX-2 inhibitor reduced the amplitude of HERG current in gastric cancer cells and PGE2 enhanced the amplitude. However, in gastric cancer cells transfected with HERG mutant deleting cAMP-binding domain, both COX-2 inhibitor and PGE2 did not show significant effects on HERG current. cAMP agonist enhanced the amplitude of HERG current and cAMP antagonist reduced the amplitude in gastric cancer cells. Both agonist and antagonist of cAMP had no significant effect on HERG current in gastric cancer cells transfected with HERG mutant deleting cAMP binding domain. PKA inhibitor did not influence the HERG current whether in parental gastric cancer cells or in gastric cancer cells transfected with HERG mutant.