Oil-based contrast for hysterosalpingography-regulated Th1/Th2-type cytokines and alleviated inflammation in rats with LPS-induced chronic endometritis.

Abstract

The chronic endometritis (CE) prevalence in people experiencing infertility is 2.8-56.8%, pregnancy rates in patients with infertility increase after hysterosalpingography with oil-based contrast, but the effect and mechanism are not clear. Here, we analyzed the effects of intrauterine ethiodized poppyseed oil (EPO) bathing on a rat model of CE and the possible underlying mechanism. CE rats were induced by lipopolysaccharide (LPS) exposure, and rats were subjected to intrauterine bathing with EPO or phosphate-buffered saline (PBS) after model verification. Serum and uterus levels of IFN-γ, IL-4, TNF-α, and IL-1β were detected by ELISA kit, and the number of CD138+ and CD68+ cells and uterine IFN-γ, IL-4, TNF-α, IL-1β, and NF-κB P65 expression were detected by immunohistochemistry after bathing. LPS exposure induced the typical CE phenotype with CD138+ phagocyte infiltration of the endometrial stroma. Compared with PBS bathing, bathing with EPO in CE rats showed decreases in the CD138+ and CD68+ cells populations and significant decreases in serum and uterine IFN-γ levels, moreover, uterine IL-4 levels were slightly higher, and the IFN-γ/IL-4(Th1/Th2-type cytokine ratio) in the uterus was significantly lower. Local IFN-γ, TNF-α, and NF-κB P65 expression in the endometrium was significantly downregulated, while IL-4 expression was upregulated. Intrauterine oil-based contrast bathing significantly alleviated local inflammation in the rat CE model by downregulating NF-κB P65 expression, reducing IFN-γ (Th1), increasing IL-4 levels (Th2) in the endometrium, and regulating the Th1/Th2-type cytokine trends toward Th2.