稻米中硒的人体生物有效性及调控机制研究

近年来我国掀起了富硒水稻开发的热潮，尤其是富硒土壤面积居全国首位的广西。然而硒的营养和毒性阈值较窄，稻米中硒的有效性及安全性备受关注。较之硒总量，硒的人体生物有效性更能科学评价硒对人体生物效应。本研究拟以动物试验验证法筛选最佳体外消化模型预测稻米中硒生物可给性，并改进细胞培养方法，建立快速模拟肠道吸收的细胞共培养模型。将体外消化/肠细胞共培养模型连用评价稻米中硒的人体生物有效性。研究不同富硒种植技术、烹饪方式对稻米中硒的人体生物有效性的影响。查明体外胃肠消化前后稻米中硒含量及形态与硒人体生物有效性的关系。评估不同富硒种植技术及烹饪方式的稻米对人体摄入硒的贡献，提出通过农业合理施硒和烹饪方式适度调整防患居民缺硒及硒过量。本项目的研究将丰富稻米中硒的人体生物有效性的理论与方法，也将为我国居民安全有效摄入稻米硒提供参考。

The developing upsurge of selenium-rich agriculture has rise in China, especially in Guangxi province, where the largest area of selenium-rich soil has been found. However, the nutritional and toxic thresholds of selenium are relatively narrow, and the bioavailability and safety of selenium in rice grain have been attracted much attention. Bioavailability of Se is an accurate predictor to assess its biological effect on human. However, there are fewer robust methods to predict bioavailability of selenium in rice grain. Thus, the objects of this study were to select the best in vitro digestion model for predicting bioaccessibility via animal (in vivo) validation test, and rapidly establish the intestinal cells co-culture model via improving cell culture method. The selected in vitro digestion model coupled with intestinal cells co-culture model was used to assess the selenium bioavailability in rice grain from different regions. Moreover, the effects of different selenium fertilizations and different cooking methods on the bioavailability of selenium in rice were assessed via in vitro/intestinal cells co-culture model, expounding the relationship among selenium content and species in rice grain and gastrointestinal digestive juices, and the bioavailability of Se. These research results can provide valuable information of the establishment of method for assessment of Se bioavialabiltiy, and the appropriate adjustment of Se fertilization and cooking methods to meet human nutrition requirements, avoiding shortages or overdoses of Se intake.