ABSTRACT
Objective To investigate the effect of neonatal overfeeding on the expression of lipid metabolic associated enzymes and molecular mechanisms in the livers of rats. Methods Male Sprague-Dawley rats were randomly assigned to litter sizes of three group ( small litters,SL group) or ten ( normal litters,NL group) on postnatal day 3. Body weight,milk intake,liver and fat pad (epididymal and retroperitonea) weight,and hepatic histological anal-ysis were recorded in week 2 and week 3,respectively. The levels of lipids were detected by the automatic biochemical analyzer. The mRNA expressions of acetyl-CoA carboxylase ( ACC) ,lipoprotein lipase ( LPL) ,liver-type fatty acid-binding protein (L-FABP), carnitine palmitoyltransferase 1(CPT1),microsomal triglyceride transfer protein (MTP), sterol regulatory element-binding protein-1c (SREBP-1c) and peroxisome proliferator activated receptorα(PPARα) in liver were determined by real time PCR;the protein expressions of SREBP-1c and PPARα were determined by Western lot. Results As early as week 2,the body weight of rats in SL group began to elevate (t=-5. 997,P<0. 001) and food intake (t=-3. 462,P=0. 002) compared with the rats in NL group,and persistent to weaning (body weight:t=-17. 019,P<0. 001;food intake:t=-2. 276,P=0. 031). By the time of 3 weeks old,SL rats increased visceral fat pad [ret-roperitonea (t=-7. 643,P<0. 001),epididymal (t=5. 997,P=0. 001)],liver weight (t=-7. 812,P<0. 001),hepatosomatic index (t=-3.829,P=0. 003) and serum triglyceride (TG) level (t=-2. 703,P=0. 022) compared with those of NL rats,as well as the level of hepatic ACC mRNA (t=-3. 751,P=0. 007),LPL (t=-2. 721,P=0. 017) and L-FABP mRNA (t=-2. 521,P=0. 026) . While CPT1 mRNA (t=-1. 531,P=0. 155) and MTP mRNA (t=-1. 741,P=0. 098) levels remained unchanged in both groups. Hepatic SREBP-1c mRNA expression increased in SL rats after 2 to 3 weeks (t=-2. 836,P=0. 016),paralleled with ACC and LPL mRNA expression;while the mRNA and protein expression of PPARα re-mained unchanged (t=-0. 854,P=0. 411). Conclusions Postnatal overfeeding can promote higher liver pad and dyslip-idemia at the time of weaning. The process may be regulated by up-regulated expression of ACC, LPL and L-FABP. SREBP-1c may be participated in the regulation of ACC,a rate-limiting enzyme involved in lipogenesis.
ABSTRACT
O desenvolvimento da programação fetal é considerado um importante fator de risco para doenças não-transmissíveis da vida adulta, incluindo doença cardíaca coronariana. Com o objetivo de investigar a associação entre nutrição materna e o desenvolvimento das artérias coronárias (AC) em embriões de camundongos estadiados; embriões de camundongos C57BL/6 nos estádios de 16-23 foram retirados de mães alimentadas com dietas de proteína normal (NP) ou de baixa proteína (LP), e as AC foram estudadas. Embora os embriões LP possuam massa corporal menor, entretanto tinham taxas de crescimento cardíaco maior, quando comparados com os embriões NP. O Plexo subepicárdico foi observado no início do período pós-somítico (estádio 16) em embriões NP, enquanto que nos embriões LP apenas no estádio 17 (P <0,01), persistindo até o estádio 18 (P <0,01). As artérias coronárias foram detectadas inicialmente no estádio 18 dos embrioes NP, já nos embriões LP foram encontradas a partir do estádio 19 (P <0,01). Núcleos apoptóticos foram observados em torno do anel aórtico peritruncal no estádio 18 em embriões NP e LP. Células FLK1+ (Fetal Liver Kinase 1 = VEGFr2 = Vascular Endothelial Growth Factor Receptor 2) apresentaram uma distribuição homogênea nos embriões NP já no estádio 18, enquanto uma distribuição semelhante nos embriões LP foi visto apenas nos estádios 22 e 23. A restrição proteica materna em camundongos leva a um atraso no crescimento do coração no período embrionário modificando o desenvolvimento do plexo peritruncal subepicárdica e diminuindo a taxa de apoptose na região do futuro orifício coronariano
Programming of fetal development is considered to be an important risk factor for non-communicable diseases of adulthood, including coronary heart disease (CHD). Aiming to investigate the association between maternal nutrition and the development of the coronary arteries (CA) in staged mice embryos, C57BL/6 mice embryos from stages 16 to 23 were taken from mothers fed a normal protein (NP) or low protein (LP) diet, and the CA were studied. Although the LP embryos had lower masses, they had faster heart growth rates when compared to the NP embryos. The subepicardial plexuses were observed earlier in the NP embryos (stage 20) than in the LP ones (stage 22) (P<0.01). Apoptotic nuclei were seen around the aortic peritruncal ring beginning at stage 18 in the NP and LP embryos. FLK1+ (fetal liver kinase 1 = VEGFr2 or vascular endothelial growth factor receptor 2) cells had a homogeneous distribution in the NP embryos as early as stage 18, whereas a similar distribution in the LP embryos was only seen at stages 22 and 23. Maternal protein restriction in mice leads to a delay in the growth of the heart in the embryonic period modifying the development of the subepicardial peritruncal plexus and the apoptosis in the future coronary orifice region