RESUMO
A high-fat diet (HFD) during pregnancy promotes fat accumulation and reduces docosahexaenoic acid (DHA) levels in the liver of the offspring at postnatal ages, which can depend on fetal sex. However, the prenatal mechanisms behind these associations are still unclear. Thus, we analyzed if an HFD alters DHA content and the expression of molecules related to fatty acid (FA) metabolism in the fetal liver. Female C57BL/6 mice were fed a control diet or HFD for 4-6 weeks before pregnancy until the gestational day (GD) 17.5. A subgroup of each diet received DHA (100 mg/Kg) orally from GD 6.5 until 16.5. On GD 17.5, maternal livers, placentas, and livers from male and female fetuses were collected for FA profiling with gas-chromatography and gene expression of molecules related to FA metabolism using qPCR. PPAR-α protein expression was evaluated using Western blot. The gene expression of placental FA transporters was also assessed. An HFD increased eicosapentaenoic acid (EPA) and decreased DHA levels and protein expression of PPAR-α in the fetal livers of both sexes. DHA increased the gene expression of Ppara, Cpt1, and Acsl1 in the livers of female fetuses. Therefore, an HFD reduces DHA levels and PPAR-α, a master regulator of gene expression, in the fetal liver. In turn, the livers of female fetuses seem to be more sensitive to DHA action.
Assuntos
Dieta Hiperlipídica , Ácidos Graxos , Camundongos , Feminino , Gravidez , Masculino , Animais , Ácidos Graxos/metabolismo , Dieta Hiperlipídica/efeitos adversos , Ácidos Docosa-Hexaenoicos/farmacologia , Placenta/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Camundongos Endogâmicos C57BL , Fígado/metabolismoRESUMO
ABSTRACT The purpose of this study was to examine how the maximal fat oxidation rate is affected in two groups of women with different fat mass percentages. Thirty-four women with sedentary behavior (aged 18-25 years) were divided into 2 groups according to their body fat percentage. (<32% of body fat was considered as a threshold following American College Sport Medicine [ACSM] indications). Body fat percentages were assessed by anthropometry, then subjects performed an adapted graded exercise test on a treadmill to determine maximal oxygen consumption and fat oxidation rates during exercise. There were significant differences (p<0.05) in maximal cardiorespiratory capacity (34.4±4.4 vs 30.4±10.4 mL x kg-1 x min-1) and maximal fat oxidation rates (0.39±0.05 vs 0.31±0.06 g x min-1) between the lower risk group when compared to the higher risk group. There was no correlation between body fat percentage (BF%) and fat oxidation rates in both groups. In conclusion, cardiorespiratory capacity and substrate oxidation are different when two groups of women divided by ACSM recommendations are considered and these results could help clinicians and trainers to prevent weight gain and/or promote body fat and body weight loss.
RESUMEN El propósito de este estudio fue examinar el cambio de la tasa de oxidación de grasas en dos grupos de mujeres con diferentes porcentajes de masa grasa. Metodología: Treinta y cuatro mujeres con comportamiento sedentario (edades de 18 a 25 años) fueron divididas en dos grupos de acuerdo con su porcentaje de masa grasa (<32% fue considerado como umbral siguiendo las indicaciones del American College Sport Medicine [ACSM]). El porcentaje de masa grasa fue medido por antropometría y luego los sujetos realizaron una prueba adaptado en trotadora eléctrica para determinar el consumo máximo de oxígeno y las tasas de oxidación durante el ejercicio. Resultados: Existieron significativas (p<0,05) en la capacidad cardiorrespiratoria (34,4±4,4 vs 30,4±10,4 mL x kg-1 x min-1) y máxima tasa de oxidación de grasas (0,39±0,05 vs 0,31±0,06 g x min-1) entre el grupo de menor riesgo cuando se compara con el de mayor riesgo. No hubo correlación entre el porcentaje de masa grasa (BF%) vs oxidación máxima de grasas. Conclusión: la capacidad cardiorespiratoria y la oxidación de sustratos fue diferente cuando dos grupos de mujeres son divididos por las consideraciones de la ACSM.