Comparative expression profiles of genes related to cellular stress and development in oocyte of goats fed with distinct concentrations of lipids

ABSTRACT

Background: Lipotoxicity is characterized by an excess of saturated fatty acids in the blood stream, in which other nonadipose cells begin to store them, thereby altering the expression of genes related to endoplasmic reticulum stress, whoseeffects have been associated with decreased oocyte quality in several species, decreased mitochondrial activity, and increasedapoptosis. The present study was conducted to investigate the lipotoxicity effect of diets with increasing fat levels on geneexpression in goats oocyte and granulosa cells.Materials, Methods & Results: Thirty does were divided into three groups of 10 animals each, which received forage andconcentrate to provide respectively 2.7% of lipids (LL group), 3.9% lipids (LI group) and 5.1% lipids (LH group) for 28days. Three days before oocyte harvest, follicular wave was synchronized by 1 mL PGF2α intramuscularly, followed bythe insertion of an intravaginal progesterone release device. Viable oocytes and granulosa cells were subjected to qRT-PCRto determine the expression of PLIN2, ATF4, CHOP10, BAX, BCL2, HSP70 genes, were checked, evaluated using thedissociation curve analysis, which obtained the following values 77.8, 80.2, 83.6, 78.0, 81.0 and 82.0ºC, respectively. Thesteps of qPCR thermal cycle was denaturation and polymerase activation, annealing and final extension.Throughout theexperimental period, blood samples were taken for cholesterol, triglycerides and total lipids measurements. Total plasmalipids determination was calculated with the following equation 2 x (cholesterol + triglycerides) × 1.1 with sensitivity ofthe assay for cholesterol was 1.472 mg/dL and for triglycerides, 2.845 mg/dL. In LH group, it was recorded a more pronounced increase in total lipids (+ 60.1%) (P < 0.05), cholesterol (+ 18.8%) and triglycerides (+ 8.5%). These increaseswere three times higher than that in LL and LI groups. All genes were expressed in oocytes...(AU)