MALDI Imaging Mass Spectrometry Reveals Lipid Alterations in Physiological and Sertoli Cell-Only Syndrome Human Testicular Tissue Sections

Abstract

Azoospermia, the absence of sperm cells in semen, affects around 15% of infertile males. Sertoli cell-only syndrome (SCOS) is the most common pathological lesion in the background of non-obstructive azoospermia and is characterised by the complete absence of germinal epithelium, with Sertoli cells exclusively present in the seminiferous tubules. Studies have shown a correlation between successful spermatogenesis and male fertility with lipid composition of spermatozoa, semen, seminal plasma or testis. The aim of this research was to discover the correlation between the Johnsen scoring system and phospholipid expressions in testicular cryosections of SCOS patients. MALDI imaging mass spectrometry is used to determine spatial distributions of molecular species, such as phospholipids. Phosphatidylcholines (PCs), phosphatidylethanolamines (PEs) and sphingomyelins (SMs) are the most abundant phospholipids in mammalian cells and testis. SMs, the structural components of plasma membranes, are crucial for spermatogenesis and sperm function. Plasmalogens, are unique PCs in testis with strong antioxidative properties. This study, using imaging mass spectrometry, demonstrates the local distribution of phospholipids, particularly SMs, PCs, plasmalogens and PEs in human testicular samples with SCOS for the first time. This study found a strong relationship between the Johnsen scoring system and phospholipid expression levels in human testicular tissues. Future findings could enable routine diagnostic techniques during microTESE procedures for successful sperm extraction.