[Effect of zinc deficiency on the protein expression of vitamin D receptor and calcium binding protein in growth-stage rats duodenal mucosa].
OBJECTIVE
To study the effect of zinc deficiency on the protein expression of vitamin D receptor (VDR) and calcium binding protein (CaBP) in growth-term rats duodenal mucosa and to clarify the mechanism of zinc deficiency affecting the calcium absorption by gene transcription.


METHODS
Thirty weaning male rats were randomly divided into three groups: zinc deficiency (ZD), paired-fed (PF) and zinc adequation (ZA). The ZA group received a diet containing 29.5 microg/g diet ad libitum; the ZD group received a diet containing less than 0.4 microg zinc/g diet ad libitum. To eliminate the effect of zinc deficiency on appetite, the PF group received a zinc-adequate diet restricted to the quantity of food consumed the previous day by the ZD rats. After 15 days feeding, duodenal mucosa was taken to measure expression of the protein of VDR and of CaBP by immunohistochemistry and Western-blotting.


RESULTS
Immunohistochemistry demonstrated that the intestinal mucosal expression of both VDR protein and CaBP protein in ZD rats significantly decreased. Analysis of the photographs showed that the number of cells expressed VDR protein in ZD rats was significantly less than that of the PF and ZA rats (P < 0.001). The number of cells which expressed VDR protein in ZD, PF, and ZA groups was 52, 162, and 220, and the number of cells which expressed CaBP protein was 169, 240 and 280 (F = 132 and 22, P < 0.001). Western-blotting showed similar results.


CONCLUSIONS
Zinc deficiency, by changing the activity of VDR, changes the protein expression of VDR, and thus affects the transcription of the target gene CaBP, resulting in the absorption of calcium that causes allo-osteogenesis.
Yu
Xiao-dan
XD
Xin Hua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute of Pediatric Research, Shanghai 200092, China.
Yan
Chong-huai
CH
Yu
Xiao-gang
XG
Gao
Yu
Y
Xu
Jian
J
Shen
Xiao-ming
XM
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D003677:Deficiency Diseases / Q000378:metabolism; D004386:Duodenum / Q000378:metabolism; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D051381:Rats / Q000254:growth & development*; D018167:Receptors, Calcitriol / Q000378:metabolism*; D014158:Transcription, Genetic; D014886:Weaning; D015032:Zinc / Q000172:deficiency*
D002135:Calcium-Binding Proteins; D018167:Receptors, Calcitriol; D015032:Zinc