Synergic effect of vitamin A and high-fat diet in adipose tissue development and nuclear receptor expression in young rats.
In order to study the effects of dietary lipids and vitamin A on the development of adipose tissues, young rats were submitted for 8 d to a control or to two cafeteria diets with normal (Caf) or higher (Caf + ) vitamin A levels. Retinoid (retinoic acid receptor (RAR) a, RARg, retinoid X receptor(RXR) alpha) and fatty acid (PPARgamma) receptor mRNA was measured in the subcutaneous white adipose tissue (Swat) and in isolated mature adipocytes by RT-PCR. The stroma vascular fraction was cultured in vitro to test the capacities of the adipocyte precursors to proliferate and differentiate.The Caf diet enriched in vitamin A resulted in an increased adiposity, due to increased adipocyte hypertrophy. This was concomitant with a lower expression of RARa and RARg mRNA (234.6 and 238.6 %) and a higher expression of PPARgamma (+59 %) in the Swat and, to a less extent,in isolated adipocytes. Positive correlations were obtained between PPARgamma mRNA and Swat weights and between PPARgamma and RXRalpha mRNA. By contrast, RARgamma mRNA and Swat masses were negatively correlated. The adipocyte precursors from Caf + Swat proliferated more,in vitro, at the beginning of the culture. This difference progressively disappeared and was totally absent after 8 d of culture, but with a higher percentage of differentiated preadipocytes (+80.3 %) in the Caf + group. In conclusion, lipids and vitamin A act synergistically on the normal growth of the adipose tissue in young rats, concomitant with an imbalance in the pattern of the nuclear receptors. These changes influence the early normal development of the endogenous adipocyte precursors.
Redonnet
Anabelle
A
Unité de Nutrition et Neurosciences (ISTAB), Université Bordeaux 1, Avenue des Facultés, Talence 33405, France.
Ferrand
Carine
C
Bairras
Céline
C
Higueret
Paul
P
Noël-Suberville
Catherine
C
Cassand
Pierrette
P
Atgié
Claude
C
D017667:Adipocytes / Q000378:metabolism; D050156:Adipogenesis / Q000187:drug effects*; D000818:Animals; D002478:Cells, Cultured; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D015870:Gene Expression; D008297:Male; D009765:Obesity / Q000378:metabolism*; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism; D000072482:Retinoic Acid Receptor alpha; D047490:Retinoid X Receptor alpha / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D050151:Subcutaneous Fat / Q000378:metabolism*; D013997:Time Factors; D014801:Vitamin A / Q000494:pharmacology*; D000097768:Retinoic Acid Receptor gamma
D004041:Dietary Fats; D047495:PPAR gamma; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; D047490:Retinoid X Receptor alpha; D014801:Vitamin A; D000097768:Retinoic Acid Receptor gamma; C000607073:Rara protein, rat