Bacterial lipopolysaccharide (LPS) impairs sperm mitochondrial membrane potential and induces sperm apoptosis in infertile men

Sana Sahnoun; Sellami Afifa; Hela Menif; Nour Louati; Salima Daoud; Hanen Sellami; Saloua Lassoued

Just Accepted

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Bacterial lipopolysaccharide (LPS) impairs sperm mitochondrial membrane potential and induces sperm apoptosis in infertile men

Sana Sahnoun , Sellami Afifa, Hela Menif, Nour Louati, Salima Daoud, Hanen Sellami, Saloua Lassoued

Abstract

Context. The lipopolysaccharide (LPS), a major component of Gram-negative bacteria membrane, is widely implicated in the pathogenesis of male reproductive system infections. Aims. This study aims to elucidate the LPS effect on sperm motility, mitochondrial membrane potential (ΔΨm) and apoptosis in human sperms. Methods. Our experimental study was carried out on Thirty-four sperm samples from male partners of infertile couples divided into fertile group (n=8) and infertile group (n=26). For each sample, two sperm suspensions were prepared: a control suspension (Non- treated with LPS) and an LPS- treated suspension (200 ng/ml). The two suspensions were incubated for 18 hours at room temperature. Sperm motility was evaluated by microscopic observation, whereas sperm mitochondrial membrane potential and apoptosis were assessed using flow cytometry after JC-10 and 7-AAD staining. Key results. In fertile group, no significant differences in sperm motility, sperm ΔΨm and apoptotic sperm rates were detected after incubation with LPS. However, in infertile group, the LPS reduced significantly sperm motility and induced significant decrease in the rates of sperm with high ΔΨm. Furthermore, a significant decrease in viable sperm rates was detected concomitantly with a significant increase of apoptotic sperm rates. Conclusions. This study revealed that LPS may impair sperm mitochondrial membrane potential and lead to the activation of some pathways responsible for sperm apoptosis in infertile men. Implications. This study likely contributes to better understand the mechanisms underlying sperm disorders induced by bacterial endotoxins in particular LPS especially in infertile men.

RD25069 Accepted 02 July 2025