ABSTRACT
Feeding flaxseed to dairy cows can modulate gene expression and PG synthesis in the uterus at the time of peri-implantation. The objectives of the present study were to determine which flaxseed components are responsible for these effects and how different endometrial cell types are affected. We evaluated the effects of six different linoleic acid (n-6):α-linolenic acid (n-3) ratios and three concentrations of the lignan enterolactone (ENL) on endometrial stromal cells (SC) and epithelial cells (EC). The mRNA abundance of genes with known or suspected roles in embryo survival or PG synthesis was evaluated, along with PGE2 and PGF2α concentrations in culture media. The mRNA abundance of several genes was modulated by different fatty acid (FA) ratios and/or ENL, and this modulation differed between cell types. The FA4 (FA at an n-6:n-3 ratio of 4) treatment (rich in n-3 FA) increased the mRNA abundance of genes that have positive effects on uterine receptivity and implantation when compared with the FA25 (FA at an n-6:n-3 ratio of 25) treatment (rich in n-6 FA). ENL decreased PGE2 and PGF2α concentrations in both cell types, and this reduction was associated with lower mRNA abundance of the PG synthase genes AKR1B1 and PTGES in SC. The combination of ENL with FA (FA4 treatment) resulted in the greatest reduction in PGF2α concentrations when compared with the addition of FA (FA4) or ENL alone. Because of the known luteolytic properties of PGF2α, a reduction in endometrial PGF2α secretion would favour the establishment and maintenance of pregnancy.
Subject(s)
4-Butyrolactone/analogs & derivatives , Dinoprost/metabolism , Dinoprostone/metabolism , Endometrium/drug effects , Fatty Acids, Omega-3/pharmacology , Fatty Acids, Omega-6/pharmacology , Lignans/pharmacology , 4-Butyrolactone/pharmacology , Aldehyde Reductase/genetics , Aldehyde Reductase/metabolism , Animals , Cattle , Cells, Cultured , Diet/veterinary , Dinoprost/genetics , Dinoprostone/genetics , Endometrium/cytology , Epithelial Cells/cytology , Epithelial Cells/drug effects , Female , Gene Expression , Intramolecular Oxidoreductases/genetics , Intramolecular Oxidoreductases/metabolism , Prostaglandin-E Synthases , RNA, Messenger/genetics , RNA, Messenger/metabolism , Reproducibility of ResultsABSTRACT
The paraoxonase (PON) gene family has 3 members, PON1, PON2 and PON3, which are known to be involved in oxidative stress-associated processes such as dyslipidemia, diabetes and coronary heart disease. Although PON3 is the least studied paraoxonase, recent findings have shown that it can significantly reduce atherosclerotic lesion formation and obesity in PON3 transgenic mice. Here, we describe the isolation and molecular characterization of the cDNA encoding the porcine PON3 gene. We also report the cloning of three porcine PON3 transcript variants resulting from alternate splicing of exons. Our results show that PON3 mRNA and protein are ubiquitously expressed in pig tissues. Moreover, the relative abundance of PON3 mRNA, measured in perirenal and subcutaneous fat tissues, is higher in obese Upton Meishan gilts compared with the leaner Large White and Ham Line gilts. PON3 mRNA levels measured in fat tissues positively correlate with subcutaneous, visceral and total body fat weights. Four single nucleotide polymorphisms (SNP) were identified in the PON3 coding sequence, and among these, an association was found between the c.449G>A polymorphism and the longissimus dorsi depth estimated breeding value (EBV) trait. Knowledge of the structure, distribution and expression profile of the porcine PON3 gene provides insights into its physiological function. Our results provide further support for involvement of PON3 in obesity-related disorders.
