Effects of an ω3 fatty acid-biased diet on luteolysis, parturition, and uterine prostanoid synthesis in pregnant mice.

The ω3 polyunsaturated fatty acids (PUFAs) are known to have beneficial effects on health and diseases, and hence their intake is encouraged. However, it remains unknown as to how ω3 PUFAs affect female reproduction processes, in which ω6 PUFA-derived prostaglandin (PG) E and PGF play crucial roles. We therefore compared female reproductive performance between ω3 PUFA-biased linseed oil diet-fed (Lin) mice and ω6 PUFA-biased soybean oil diet-fed (Soy) mice. In Lin mice, the uterine levels of arachidonic acid (AA) and eicosapentaenoic acid (EPA) were 0.42 fold and 16 fold of those in Soy mice, respectively, with the EPA/AA ratio being 0.7 (vs 0.02 in Soy mice). Lin mice showed no alterations in any of the fertility indexes, including luteolysis and parturition. The uterine PG synthesis profiles of Lin mice were similar to those of Soy mice, but the levels of PGF and PGE were 50% of those in Soy mice, as a result of the increased EPA/AA ratio. PGF and PGE were undetectable in the uterine tissues of Soy and Lin mice. Interestingly, in Lin mice, 'luteolytic' PGF synthesis was considerably maintained even in the ω6 PUFA-reduced condition. These results suggest the existence of an elaborate mechanism securing PGF synthesis to a level that is sufficient for triggering luteolysis and parturition, even under ω6 PUFA-reduced conditions.