断奶前后仔猪十二指肠、空肠和回肠SGLT1 mRNA表达的变化及半胱胺的影响

研究断奶前后仔猪十二指肠、空肠和回肠SGLT1mRNA表达丰度的变化,并同时观察半胱胺对其表达的影响,从分子水平探讨半胱胺对断奶仔猪葡萄糖吸收的影响与可能的机制。新生仔猪随机分为对照组和实验组,12日龄(D12)起对照组饲喂基础乳猪料,实验组在基础乳猪料中添加120mg/kg半胱胺,两组仔猪均于35日龄断奶,每组分别于断奶前1周、断奶当天、断奶后3d、1周以及断奶后10d随机选取仔猪各6头,宰杀后采集十二指肠、空肠和回肠粘膜,采用RT-PCR方法测定钠-葡萄糖共转运载体1(sodium-glucosecotransporter1,SGLT1)mRNA表达的相对丰度。结果表明,回肠SGLT1mRNA的表达量最高,空肠其次,十二指肠最低;SGLT1mRNA在不同肠段的表达呈现截然不同的发育模式,十二指肠SGLT1mRNA表达量在45d显著上升(P<0.05),而空肠则在42和45d时显著下降(P<0.01),回肠SGLT1mRNA表达在整个实验期间无显著变化;此外,日粮添加半胱胺显著提高38d十二指肠以及42和45d空肠SGLT1mRNA表达,而对回肠SGLT1mRNA表达无显著影响。小肠SGLT1mRNA表达以及日粮添加半胱胺促进SGLT1mRNA表达的作用均呈现时空特异性规律。

Expression of SGLT1 mRNA in Duodenum, Jejunum and Ileum of Weaning Piglets and the Effect of Cysteamine on It

To investigate the patterns of sodium-glucose co-transporter 1(SGLT1) expression in duodenum, jejunum and ileum of weaning piglets and the effects of cysteamine, and to explore its possible mechanism, newborn piglets were allocated to control and treatment groups. From 12 d of age(D12), piglets in control group were fed basal diet, while the treatment group received basal diet supplemented with 120 mg/kg cysteamine. Piglets were weaned at D35 in both groups. Six piglets from each group (n = 6) were slaughtered on D28(one week before weaning), D35(weaning), D38, D42 and D45(3, 7 and 10 d after weaning), respectively. Mucosal tissue was collected from three different segments of small intestine(duodenum, jejunum and ileum) and a semi-quantitative RT-PCR was applied to determine the abundances of SGLT1 mRNA. Results showed that the highest expression of SGLT1 mRNA was detected in ileum, followed by jejunum and duodenum. The patterns of age-related change in SGLT1 mRNA expression were distinct in different segments of small intestine. The abundance of SGLT1 mRNA in duodenum increased significantly at D45 (P <0.05), while in jejunum a significant down-regulation was observed at D42 and D45 (P <0.01). In contrast, ileal expression of SGLT1 mRNA kept stable throughout the experiment. Cysteamine significantly improved the expression of SGLT1 mRNA in duodenum and jejunum after weaning, but did not affect the SGLT1 mRNA expression in ileum. The results indicate that the expression of SGLT1 mRNA is spatio-temporal specific in small intestine of weaning piglets, and that cysteamine affects the expression of SGLT1 in a spatio-temporal specific manner.