Ovarian stimulation induces high expression of interleukin-1β and disrupts the histological features of the fallopian tube

Abstract

The objective of this study was to investigate whether there is an association between ovarian stimulation and interrupted gameteinteraction in the rat fallopian tube in vivo. We evaluated the protein expression of interleukin-1β (IL-1β) via immunohistochemistryand assessed the key histological features of the ovaries, fallopian tubes, and uteri of the rats following treatment with mild (15 IU)and high (30 IU) doses of gonadotropins compared to an unstimulated control group. The serum concentration of estradiol was alsodetermined by immunoassay. The results revealed that high levels of circulating estrogen were associated with higher expression ofthe IL-1β protein in the ovaries and fallopian tubes of highly stimulated rats than in those of the mildly stimulated and unstimulatedcontrol groups. In contrast, endometrial IL-1β immunoexpression was not affected by ovarian stimulation. The histological features ofthe fallopian tubes were also dramatically altered upon ovarian stimulation, reducing the efficiency of the fallopian tube. In conclusion,the resulting high circulating estrogen level disrupts the histological features of the fallopian tubes and can lead to higher expression ofIL-1β, thus negatively affecting gamete interactions in vivo. These results provide useful information regarding the lower fertilizationrate observed following ovarian stimulation.