Polydatin attenuated food allergy via store-operated calcium channels in mast cell.

AIM: To investigate the effect of polydatin (PD), a resveratrol glucoside, on mast cell degranulation and anti-allergic activity. METHODS: After the rats were orally sensitized with ovalbumin (OVA) for 48 d and underwent PD treatment for 4 d, all the rats were stimulated by 100 mg/mL OVA for 24 h and then sacrificed for the following experiments. The small intestines from all the groups were prepared for morphology examination by hematoxylin and eosin staining. We also used a smooth muscle organ bath to evaluate the motility of the small intestines. The OVA-specific immunoglobulin E (IgE) production and interleukin-4 (IL-4) levels in serum or supernatant of intestinal mucosa homogenates were analyzed by enzyme-linked immunosorbent assay (ELISA). Using toluidine blue stain, the activation and degranulation of isolated rat peritoneal mast cells (RPMCs) were analyzed. Release of histamine from RPMCs was measured by ELISA, and regulation of PD on intracellular Ca(2+) mobilization was investigated by probing intracellular Ca(2+) with fluo-4 fluorescent dye, with the signal recorded and analyzed. RESULTS: We found that intragastric treatment with PD significantly reduced loss of mucosal barrier integrity in the small intestine. However, OVA-sensitization caused significant hyperactivity in the small intestine of allergic rats, which was attenuated by PD administration by 42% (1.26 ± 0.13 g vs OVA 2.18 ± 0.21 g, P < 0.01). PD therapy also inhibited IgE production (3.95 ± 0.53 ng/mL vs OVA 4.53 ± 0.52 ng/mL, P < 0.05) by suppressing the secretion of Th2-type cytokine, IL-4, by 34% (38.58 ± 4.41 pg/mL vs OVA 58.15 ± 6.24 pg/mL, P < 0.01). The ratio of degranulated mast cells, as indicated by vehicles (at least five) around the cells, dramatically increased in the OVA group by 5.5 fold (63.50% ± 15.51% vs phosphate-buffered saline 11.15% ± 8.26%, P < 0.001) and fell by 65% after PD treatment (21.95% ± 4.37% vs OVA 63.50% ± 15.51%, P < 0.001). PD mediated attenuation of mast cell degranulation was further confirmed by decreased histamine levels in both serum (5.98 ± 0.17 vs OVA 6.67 ± 0.12, P < 0.05) and intestinal mucosa homogenates (5.83 ± 0.91 vs OVA 7.35 ± 0.97, P < 0.05). Furthermore, we demonstrated that administration with PD significantly decreased mast cell degranulation due to reduced Ca(2+) influx through store-operated calcium channels (SOCs) (2.35 ± 0.39 vs OVA 3.51 ± 0.38, P < 0.01). CONCLUSION: Taken together, our data indicate that PD stabilizes mast cells by suppressing intracellular Ca(2+) mobilization, mainly through inhibiting Ca(2+) entry via SOCs, thus exerting a protective role against OVA-sensitized food allergy.

[Effect of transfection of hEndostatin gene on CNE2 cell xenograft growth in nude mice].

BACKGROUND & OBJECTIVE: Tumor angiogenesis play an important role in growth and metastasis of cancer. Angiogenesis inhibitors induce apoptosis in cancer by inhibiting tumor angiogenesis and have strong inhibiting effect on both growth and metastasis of cancer. This study was designed to explore the effect of transfection of human endostatin gene on nasopharyngeal carcinoma CNE2 cells xenograft growth in nude mice. METHODS: The plasmids (pBlast-hIL-hEndostatin, pBlast-hEndostatin, and pBlast-MCS) were transfected and lipofectin-mediated into the CNE2 cell line. The biological activity of secreted hEndostain from gene-transferred cell lines was determined using MTT method in vitro. Then the transfected CNE2 cells were injected into the nude mice and tumorigenicity of CNE2 was observed in vivo. RESULTS: The supernatant of CNE2 cell transfected with pBlast-hIL-hEndostatin effectively inhibited the growth of endothelial cell (ECV304). The volume and the weight of tumor in pBlast-hIL -hEndostatin transfecting cells group were less than those in control group (P< 0.01). The growth speed of tumor in pBlast-hIL-hEndostatin transfecting cells group was slower than that in control group. CONCLUSION: Transfection of hEndostatin gene could inhibit CNE2 cell growth in nude mice.