Expression of peroxisome proliferator activated receptor gamma 2 and its target genes in visceral fat tissue of growth restricted offspring in rats

Abstract

Objective To investigate the expression of transcription factor peroxisome proliferator activated receptor gamma 2 （PPAR2） and its target genes--adipose differentiation-related protein （ADFP） and phosphoenolpyruvate carboxykinasel （PCK1） in visceral fat of growth restricted rat offspring, in order to explore their effects on the incidence of obesity and metabolism syndrome. Methods Fetal growth restriction （FGR） rat model was established by maternal low-protein diet and only male offsprings were studied. The mRNA expressions of PPAR2, ADFP and PCK1 in perirenalfat tissues were measured at 3 week （W3） and 8 week （W8）-old rats by real time quantitative reverse transcription-polymerase chain reaction （real-time-RT-PCR）. PPAR）2, ADFP and PCK1 protein levels in the perrenal fat tissues were determined by Western blot. Statistical analysis was performed with t-test and Spearman linear correlation analysis. Results The PPAR2 mRNA level in perrenal fat tissue of FGR rats at W3 and W8 were significantly elevated than that of the controls （W3：2.43 0.38 vs 1.034-O. 11,t=2.74,PO. O5;W8：2.170.34 vs 1.074-O. 14,t=2.49,PO. 05）, and PPAR/2 protein content was also increased （W3：l. 070.17 vs 0.41±0.06,t=3.01,P0.05;W8： 1.29±0.20 vs0.68--0.09,t=2.62,P0.05）, which equal to （261±31） and （19024） % of control, respectively. Increased mRNA and protein levels of the target genes ADFP and PCK1 in perrenal fat tissue were also found in the FGR rats at W3 and W8 compared with the same aged control rats （ADFP mRNA at W3..1. 874-0.29 vs 1.02=0. 12,t=2.20;ADFP mRNA at W8：1.64 0.31 vs 1.064-0.14,t=3.47; PCK1 mRNA at W3：2.030.26 vs 0.980.08,t=2.97;PCK1 mRNA at W8：l. 79±0.28 vs 1. 034-0.11,t=3.24; ADFP protein at W3 ： 0. 43 = 0. 06 vs 0. 14= 0. 03 , t= 3. 01; ADFP protein at W8：0.71=0.09 vs 0.38＋0.05,t=3.06;PCK1 protein at W3： 0.820. 10 vs 0. 394-0.05,t=2.65;PCK1 protein at WS： 0.85＋0.11 vs 0. 674-0.07,t=2.86; all P%0.05）. The protein and mRNA expressions of ADFP and PCK1 were positively correlated with expression the levels ofPPAR72 （mRNA：r 0.907 and 0.826,both P%0.01;protein：r=0.763 and 0. 805,both P0.05）. Conclusions Intrauterine programming＂ increases the expression of PPAR2 in perrenal adipose tissue of FGR individuals, which might contribute to the increased expressions of its target genes ADFP and PCK1, thereby causes the accumulation of adipose cells and subsequently promotes obesity and metabolism syndrome in adulthood. Key words: Fetal growth retardation; Adipose tissue; PPAR gamma; Membrane proteins; Phosphoenolpyruvate carboxykinase （GTP）; Intracellular signaling peptides andproteins