New insights into sperm with total globozoospermia: Increased fatty acid oxidation and centrin1 alteration

Sperm morphology and lipid profile have a relevant role in male fertility. We explore the status of the sperm centriole, essential structure for human fertilization and the role of fatty acid oxidation in globozoospermia, a rare sperm pathology causing infertility. A case of globozoospermia was characterized by light and electron microscopy, sperm immunolocalization was performed for centrin1, 8-iso-PGF_2α and peroxisome proliferator γ activated receptor gamma (PPARγ). In semen and sperm pellet, F₂-isoprostanes (F₂-IsoPs) levels were determined. Finally, the cytosolic phospholipase A₂ (cPLA₂) assessment was carried out in spermatozoa. The experiments were also performed in sperm from three fertile men. The results of electron microscopy analysis showed spermatozoa were round-headed without acrosome and with tail coiled around the nucleus characterized by immature chromatin. Centrin1 was located around the head in globozoospermic sperm, whereas, in sperm of controls, it appears as two spots. The 8-iso-PGF_2α was detected around the head and in the cytoplasmic residue; PPARγ was mainly present in the cytoplasmic residue and under the head. The fluorescent signals for all molecules were different in the sperm of fertile men. F₂-IsoPs levels, determined both in semen and sperm, were significantly increased (P < 0.05) and sperm cPLA₂ was significantly decreased (P < 0.05) in the globozoospermic patients versus fertile subjects. In conclusion, sperm with globozoospermia showed an increased susceptibility to non-enzymatic fatty acid oxidation that could be, at least in part, responsible for fertilization failure in intracytoplasmic sperm injection. The opportunity to study a peculiar sperm pathology, as globozoospermia, could provide new insights in the relationship between lipid peroxidation and male infertility. Abbreviations: PPARγ: peroxisome proliferator γ activated receptor gamma; F₂-IsoPs: F₂-isoprostanes; cPLA₂: cytosolic phospholipase A₂; ICSI: Intracytoplasmic Sperm Injection; PLCζ: phospholipase C zeta; PUFAs: polyunsaturated fatty acid; AA: arachidonic acid; PLA₂: phospholipase A₂; SEM: scanning electron microscopy; TEM: transmission electron microscopy; AB: aniline blue; AO: acridine orange; FA: fatty acid; 8-iso-PGF_2α: 8-iso-prostaglandin F_2α; WHO: World Health Organization; DAPI: 4,6-Diamidino-2-phenylindole; PBS: phosphate buffered saline; GC/NICI-MS/MS: gas chromatography/negative-ion chemical ionization tandem mass spectrometry; BHT: butylated hydroxytoluene; PGF_2α-d4: tetradeuterated derivative of Prostaglandin F_2α; ELISA: enzyme-linked immunosorbent assay.