Estradiol is a steroid hormone that not only plays an important role in ovarian follicular development but also is associated with many reproductive disorders. Owing to the importance of aromatase in the production of estradiol, the regulation of aromatase gene expression at the transcriptional level has been an extensive area of study for over two decades. However, its regulation at the posttranscriptional level has remained unclear. Here, we show that micro-RNA378 (miR-378) is spatiotemporally expressed in porcine granulosa cells, the cells that generate estradiol in the ovary during follicular development, in an inverse manner compared with the expression of aromatase. In vitro overexpression and inhibition experiments revealed that aromatase expression, and therefore estradiol production, by granulosa cells, is posttranscriptionally down-regulated by miR-378. Furthermore, site-directed mutation studies identified two binding sites in the 3′-untranslated region (3′-UTR) of the aromatase coding sequence that are critical for the action of miR-378. Interestingly, overexpression of the aromatase 3′-UTR enhanced aromatase expression at the protein level in granulosa cells, possibly mediated by the binding of miR-378 within this region, thereby reducing the binding of this micro-RNA to the endogenous aromatase 3′-UTR.

Background: Beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs) on the reproduction of male animals are widely described in the literature. However, there is little information about the effect of n-3/n-6 PUFA ratios on male health and reproduction. The aim of this study was to investigate the effects of diets with different n-3/n-6 PUFA ratios on the reproductive performance of male rats. Methods: Eighty male Sprague Dawley (SD) rats were supplemented with diets containing different n-3/n-6 PUFA ratios (0.13, 0.40, 0.85, 1.52 and 2.85) for 60 days. Half of the rats in each group were sacrificed on day 60, and the other half were chosen to mate with female mice to assess the effects of n-3/n-6 ratios on reproductive performance. Results: Sperm density and sperm motility of the 1.52 group were higher than other groups (P < .05), and the development of testis and the morphological structure of sperm in the 1.52 group were better than other groups. Furthermore, a higher litter size and birth weights of offspring were observed in the 1.52 group. Additionally, serum reproductive hormone levels were significantly affected by the n-3/n-6 ratios. Conclusion: These findings demonstrated that a balanced n-3/n-6 ratio was important in male rat reproduction. Therefore there is a necessity to determine an appropriate n-3/n-6 PUFA ratio in man and different male animals in the future.