Effects of omega-3 and -6 polyunsaturated fatty acids on ovine follicular cell steroidogenesis, embryo development and molecular markers of fatty acid metabolism.
We previously reported increased follicular fluid progesterone (P(4)) concentrations in ewes fed an n-3 compared to an n-6 polyunsaturated fatty acid (PUFA)-enriched diet, but detected no differential effect of n-3 and n-6 PUFA-enriched high-density lipoproteins (HDL) on granulosa cell (GC) steroidogenesis in vitro. Moreover, net n-6 PUFA-enriched HDL reduced early embryo development, but in the absence of a net uptake of FA. Consequently, we hypothesised that a) effects of n-3 PUFA on ovarian steroidogenesis are mediated by theca rather than GCs and b) during embryo culture lipids are acquired solely from the albumin fraction of serum, so that albumin-delivered n-3 and n-6 PUFA exert a greater differential effect on embryo development than either low-density lipoprotein (LDL)- or HDL-delivered PUFA. Data confirmed that n-3 PUFA increases P(4) production solely in theca cells and that this is associated with an increase in STAR transcript expression. Furthermore, LDL- and HDL-delivered n-3 PUFA are equally efficacious in this regard during the first 96 h of culture, but thereafter only HDL-delivered n-3 PUFA induces this effect in partially luteinised theca cells. We also demonstrate that albumin is the sole serum fraction that leads to a net uptake of FA during embryo culture. PUFA-enriched serum and albumin increased the yield of morphologically poorer quality blastocysts with increased transcript expression for the antioxidant enzyme SOD1. Important differential effects of n-3 and n-6 PUFA on ovarian steroidogenesis acting solely on theca cells are identified, but differential effects of PUFA on embryo development are less apparent.
Schools of Biosciences Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire, UK.
Jaime
J
Hughes
Wing Yee
WY
Kwong
Dongfang
D
Li
Andrew M
AM
Salter
Richard G
RG
Lea
Kevin D
KD
Sinclair
D000818:Animals; D001755:Blastocyst / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D046149:Embryo Culture Techniques; D005227:Fatty Acids / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6 / Q000494:pharmacology*; D005260:Female; D015571:Follicular Fluid / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism; D008075:Lipoproteins, HDL / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism; D006080:Ovarian Follicle / Q000187:drug effects* / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011374:Progesterone / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000378:metabolism; D012709:Serum Albumin / Q000378:metabolism; D012756:Sheep; D013799:Theca Cells / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors; D000098682:Steroidogenic Acute Regulatory Protein
D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D010750:Phosphoproteins; D012333:RNA, Messenger; D012709:Serum Albumin; D000098682:Steroidogenic Acute Regulatory Protein; D011374:Progesterone