Nitrosative stress in human spermatozoa causes cell death characterized by induction of mitochondrial permeability transition-driven necrosis

• 来源期刊: 亚洲男性学杂志（英文版）
• 年，卷（期）: 2018,（6）
• 页码范围: 600-607
• 页数: 8页
• 语种: 英文

摘要

Peroxynitrite is a highly reactive nitrogen species and a potent inducer of apoptosis and necrosis in somatic cells.Peroxynitrite-induced nitrosative stress has emerged as a major cause of impaired sperm function;however,its ability to trigger cell death has not been described in human spermatozoa.The objective here was to characterize biochemical and morphological features of cell death induced by peroxynitrite-mediated nitrosative stress in human spermatozoa.For this,spermatozoa were incubated with and without (untreated control) 3-morpholinosydnonimine (SIN-1),in order to generate peroxynitrite.Sperm viability,mitochondrial permeability transition (MPT),externalization of phosphatidylserine,DNA oxidation and fragmentation,caspase activation,tyrosine nitration,and sperm ultrastructure were analyzed.The results showed that at 24 h of incubation with SIN-1,the sperm viability was significantly reduced compared to untreated control (P ＜ 0.001).Furthermore,the MPT was induced (P ＜ 0.01) and increment in DNA oxidation (P ＜ 0.01),DNA fragmentation (P ＜ 0.01),tyrosine nitration (P ＜ 0.0001) and ultrastructural damage were observed when compared to untreated control.Caspase activation was not evidenced,and although phosphatidylserine externalization increased compared to untreated control (P ＜ 0.001),this process was observed in ＜10％ of the cells and the gradual loss of viability was not characterized by an important increase in this parameter.In conclusion,peroxynitrite-mediated nitrosative stress induces the regulated variant of cell death known as MPT-driven necrosis in human spermatozoa.This study provides a new insight into the pathophysiology of nitrosative stress in human spermatozoa and opens up a new focus for developing specific therapeutic strategies to better preserve sperm viability or to avoid cell death.