# Investigation of Phosphatidylcholine by MALDI Imaging Mass Spectrometry in Normal and IVF Early-Stage Embryos

## TL;DR

The study uses mass spectrometry to show how lipid levels change in mouse embryos and uterine tissues during normal and IVF pregnancies.

## Contribution

This is the first study to demonstrate spatio-temporal lipid metabolism changes during IVF procedures using MALDI imaging.

## Key findings

- PC 32:0 and PC 34:0 increased in embryonal tissues during IVF.
- PC 36:4 and PC 38:4 increased in antemesometrial decidua.
- Lipid expression patterns differ between normal and IVF pregnancies.

## Abstract

The receptive phase of the uterus is marked by structural and functional maturation of the endometrium. During this limited time span, the blastocyst competency is superimposed on the receptive endometrium. It is a well-known fact that lipid signalling in early-stage pregnancy has a crucial role in successful embryogenesis. In our study, CD-1 mouse uteri after normal and in vitro fertilization (IVF) were investigated at 6.5, 8.5, and 10.5 days of pregnancy. Matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry and liquid chromatography coupled tandem mass spectrometry were used for identification of phosphatidylcholine (PC) lipid structures. In the embryonal tissues, PC 32:0 and PC 34:0 were increased, while in the antemesometrial (AM) decidua the two 20:4-containing PCs, PC 36:4 and PC 38:4 were increased. In transferred uterus samples, higher expressions of PC 34:0, PC 34:1, PC 34:2, PC 36:1, and PC 36:2 in mesometrial decidua were seen, whereas the two 20:4-containing PCs, PC 36:4 and PC 38:4 showed increased expression in the AM and lateral decidua. This paper shows a significant spatio-temporal change in lipid metabolism during IVF procedures for the first time.