Effects of duodenal redox status on calcium absorption and related genes expression in high-fat diet–fed mice

• Published in: Nutrition (Burbank, Los Angeles County, Calif.) Vol. 26; no. 11; pp. 1188 - 1194
• Main Authors: Xiao, Ying, M.S, Cui, Jue, M.S, Shi, Yong-Hui, M.S, Sun, Jin, Ph.D, Wang, Zhou-Ping, Ph.D, Le, Guo-Wei, Ph.D
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.11.2010; [New York]: Elsevier Science Inc; Elsevier; Elsevier Limited
• Subjects: animal models; Animals; antioxidant activity; Antioxidants - metabolism; Antioxidants - therapeutic use; Biological and medical sciences; Biomarkers - blood; Biomarkers - metabolism; Bone Density; Bones; Calbindins; Calcium; Calcium - administration & dosage; Calcium - metabolism; Calcium, Dietary - therapeutic use; Diet; Dietary Fats - adverse effects; dietary minerals; Dietary Supplements; Duodenum; Duodenum - enzymology; Duodenum - physiology; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; Gastroenterology and Hepatology; Gene expression; Gene Expression Regulation; Glutathione - blood; Glutathione - metabolism; High-fat diet; Intestinal Absorption; Intestinal calcium absorption; Male; Mice; Mice, Inbred C57BL; nutrition-genotype interaction; Oxidation-Reduction; Oxidative Stress; Oxidoreductases - blood; Oxidoreductases - metabolism; Plasma Membrane Calcium-Transporting ATPases - genetics; Plasma Membrane Calcium-Transporting ATPases - metabolism; Proteins; Random Allocation; Reactive oxygen species; Reactive Oxygen Species - blood; Reactive Oxygen Species - metabolism; redox reactions; Reduced glutathione; Rodents; S100 Calcium Binding Protein G - genetics; S100 Calcium Binding Protein G - metabolism; Sodium-Calcium Exchanger - genetics; Sodium-Calcium Exchanger - metabolism; Thioctic Acid - therapeutic use; Transcellular transport; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vitamin D; Reduced glutathione; Reactive oxygen species; Intestinal calcium absorption; Duodenum; High-fat diet; Transcellular transport; Gene expression; Calcium; Digestive system; Biological transport; Rodentia; Small intestine; Feeding; Vertebrata; Absorption; Mammalia; Diet; Mouse; Animal; Fat; Glutathione
• ISSN: 0899-9007; 1873-1244
• DOI: 10.1016/j.nut.2009.11.021

Abstract Objective This study investigated whether duodenal redox imbalance induced by high-fat diet (HFD) influenced expression of genes involved in transcellular calcium absorption, thus leading to reduced intestinal calcium absorption. Methods Male C57BL/6 mice were randomly assigned to one of four groups with eight mice in each group. The control group consumed an ordinary diet (4.9% fat, w/w). The other three groups were fed a HFD (21.2% fat), the HFD plus 0.1% lipoic acid, or the HFD plus an additional 0.9% calcium supplement. After 9 wk, plasma and duodenal oxidative stress biomarkers including malondialdehyde, superoxide dismutase, catalase, total antioxidant capacity, reduced glutathione/oxidized glutathione ratio, and reactive oxygen species were examined. The intestinal calcium absorption state was evaluated through examining the calcium balance, bone mineral density, and calcium metabolism biomarkers. Furthermore, quantitative reverse transcription–polymerase chain reaction was carried out to analyze the changes in expression of transcellular calcium absorption-related genes. Results The HFD induced marked decreases in intestinal calcium absorption and bone mineral density of the whole body, accompanied by redox imbalance and increased oxidative damage in duodenum; duodenal expression of calbindin-D9K , plasma membrane calcium ATPase (PMCA1b ), and sodium-calcium exchanger was significantly down-regulated by 1.9-, 2.7-, and 1.5-fold, respectively. Furthermore, duodenal glutathione and oxidized glutathione (GSH/GSSG) ratios were strongly positively correlated with the apparent calcium absorption rate and the expression of PMCA1b and Calbindin-D9K , whereas reactive oxygen species levels were negatively correlated with them. Conclusion Our results demonstrated that a HFD-induced duodenal oxidation state could significantly down-regulate expression of calbindin-D9K , PMCA1b , and sodium-calcium exchanger, thus causing an inhibitory effect on intestinal calcium absorption.