High-fat diet up-regulates caveolin-1 expression in aorta of diet-induced obese but not in diet-resistant rats.
OBJECTIVE
Caveolin-1 (Cav-1) is considered as a negative regulator of endothelial nitric oxide synthase (eNOS) and influences various cardiovascular functions. The objective of the study is to investigate the effects of high-fat diet on vascular Cav-1 expression and eNOS activities.


METHODS
Male outbred Sprague-Dawley rats were fed with a high-fat diet for 15 weeks to induce obesity. The diet-induced obese (DIO) rats were then divided into two groups. One group (DIO-LF) was fed a normal diet and another group (DIO-HF) along with diet-resistance (DR) rats were fed a high-fat diet for 8 more weeks. Cav-1 expression was determined using reverse transcription (RT)-PCR, Western blotting, and immunohistochemistry techniques. NOS activities were assessed using Griess reagents. Protein kinase B (PKB/Akt) and eNOS expression and phosphorylation were determined by Western blotting.


RESULTS
A high-fat diet up-regulated Cav-1 and down-regulated eNOS expression in aorta of DIO rats, but not in that of DR rats. These effects were reversed in DIO rats after switching to a low-fat diet for 8 weeks. Decreased NOS activities in aortas were observed in DIO rats, but not in DR rats. Phosphorylation of PKB/Akt and eNOS (Ser1177) were enhanced in aortas of DIO rats of both DIO-HF and DIO-LF groups.


CONCLUSIONS
These findings suggest that the decrease of vascular NOS activities in rats fed a high-fat diet were due, at least in part, to the up-regulation of Cav-1 expression.
Yang
Nianhong
N
Department of Nutrition & Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430030, PR China.
Ying
Chenjiang
C
Xu
Mingjia
M
Zuo
Xuezhi
X
Ye
Xiaolei
X
Liu
Liegang
L
Nara
Yasuo
Y
Sun
Xiufa
X
D000818:Animals; D001011:Aorta; D015153:Blotting, Western / Q000379:methods; D051242:Caveolin 1 / Q000235:genetics* / Q000378:metabolism; D004041:Dietary Fats / Q000008:administration & dosage*; D007150:Immunohistochemistry; D008297:Male; D052250:Nitric Oxide Synthase Type III / Q000032:analysis / Q000378:metabolism; D009765:Obesity / Q000378:metabolism*; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
D051242:Caveolin 1; D004041:Dietary Fats; D012333:RNA, Messenger; D052250:Nitric Oxide Synthase Type III; D051057:Proto-Oncogene Proteins c-akt