With the increased utilization of assisted reproductive technology (ART), concerns about the potential health risks for ART-conceived babies have also been raised. Increased prevalences of allergic and metabolic diseases have been reported among ART offspring. This study aimed to evaluate the impact of IVF on the tendency to develop allergic responses following ovalbumin (OVA) sensitization in IVF-conceived mice. Mice were divided into four groups (non-OVA naturally conceived, OVA naturally conceived, non-OVA IVF-conceived, and OVA IVF-conceived). In the OVA groups, the mice were subjected to intraperitoneal and intranasal immunization with OVA. Two days after the final immunization, blood samples were taken, and the serum levels of IgE and IL-4 were detected by ELISA. The mice were sacrificed by cervical dislocation, their spleens and lungs were removed, and their weights were measured and recorded. Sensitization with OVA resulted in significantly increased concentrations of IL-4 and total IgE, as well as increased lung and spleen weights, among offspring from both natural and IVF conception. The concentrations of IgE and IL-4 and the lung and spleen weights in IVF-conceived mice were significantly higher compared to those in naturally conceived mice before and after sensitization with OVA. It is concluded that compared to naturally conceived mice, IVF-conceived mice exhibit a greater tendency to develop allergic responses against OVA.

Background: Due to the difficulty of identifying the window of receptivity, a molecular understanding of endometrial changes after fertilization is essential for improving the effectiveness of in vitro fertilization (IVF). This multi-level study examines the compo-sition of cytokines and extracellular vesicles (EVs) in uterine lavage samples obtainable via a noninvasive procedure in mice. The goal is to offer a new perspective on the tim-ing of embryo transfer. Methods: We performed flow cytometric analyses of inflamma-tory cytokines and EVs in uterine lavage samples collected from CD1 mice at the pre-receptive stage (2.5 days post coitum [dpc]) and the receptive stage (4.5 dpc). We also assessed endometrial progesterone receptor expression via immunohistochemistry and evaluated the expression of adhesion molecules related to implantation by RT-PCR. Re-sults: Significant differences were found in the concentrations of inflammatory cyto-kines (IL-6, IFN-γ, and MCP-1), the EV pattern in uterine lavage fluid, and the expres-sion of some genes related to implantation (CD44, CD81, and CD29). These results re-veal uterine lavage fluid markers associated with endometrial receptivity. Using these noninvasive markers can improve the effectiveness of IVF by enabling more precise timing of embryo transfer.