Original Article
Copyright ©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Jul 7, 2013; 19(25): 3980-3989
Published online Jul 7, 2013. doi: 10.3748/wjg.v19.i25.3980
Polydatin attenuated food allergy via store-operated calcium channels in mast cell
Bo Yang, Jian-Jie Li, Ji-Juan Cao, Cheng-Bin Yang, Jie Liu, Qiong-Mei Ji, Zhi-Gang Liu
Bo Yang, Jian-Jie Li, Cheng-Bin Yang, Qiong-Mei Ji, Zhi-Gang Liu, Allergy Branch of the State Key Laboratory of Respiratory Disease, School of Medicine, Shenzhen University, Shenzhen 518060, Guangdong Province, China
Ji-Juan Cao, Liaoning Entry-Exit Inspection and Quarantine Bureau, Dalian 116001, Liaoning Province, China
Jie Liu, Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, Guangdong Province, China
Author contributions: Yang B, Li JJ, Liu J, Ji QM and Liu ZG designed the research; Yang B, Li JJ, Cao JJ and Yang CB performed the experiments; Yang B and Li JJ analyzed the data and wrote the manuscript; Yang B, Liu J and Liu ZG edited the manuscript; Yang B and Li JJ contributed equally to this work.
Supported by The Natural Science Foundation of China, No. 81271950, to Ji QM; Projects of International/HMT (Hong Kong, Macau, and Taiwan) Cooperation and Innovation Platform in Science and Technology of Guangdong Higher Education Institutions, No. 2012gjhz0009, to Liu ZG; Key Laboratory Construction Program of Shenzhen, No. SW201110010, to Liu ZG; and Basic Research Program of Shenzhen University, No. 201101, to Liu ZG; Basic Research Foundation of Shenzhen, No. JC201005250059A, JCYJ20120613115535998
Correspondence to: Zhi-Gang Liu, Professor, MD, PhD, Allergy Branch of the State Key Laboratory of Respiratory Disease, School of Medicine, Shenzhen University, Rm722, Composite Building, Nan Hai Ave 3688, Shenzhen 518060, Guangdong Province, China. lzg@szu.edu.cn
Telephone: +86-755-86671907 Fax: +86-755-86671906
Received: February 22, 2013
Revised: April 10, 2013
Accepted: May 16, 2013
Published online: July 7, 2013
Processing time: 134 Days and 7 Hours
Abstract

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 Ca2+ mobilization was investigated by probing intracellular Ca2+ 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 Ca2+ 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 Ca2+ mobilization, mainly through inhibiting Ca2+ entry via SOCs, thus exerting a protective role against OVA-sensitized food allergy.

Keywords: Polydatin; Food allergy; Mast cells; Store-operated calcium channels; Ca2+

Core tip: In the present study, we have demonstrated for the first time that polydatin has the capacity for preventing pathogenesis of food allergy, which is dependent on regulation of Ca2+ mobilization via store-operated calcium channels in mast cells.