Associations between seminal plasma osteopontin level and sperm motility in infertile men with asthenozoospermia

Abstract

Purpose: Male infertility, a complex multifactorial condition, is frequently caused by asthenozoospermia (AZS). Although osteopontin (OPN) has been implicated in mammalian reproduction, its specific effects on sperm motility and fertility are not well understood. This study investigates the relationships between seminal plasma OPN levels and sperm parameters in cases of male infertility.

Methods: A total of 158 semen samples were analyzed, comprising 78 from infertile men with AZS and 80 from healthy fertile controls. OPN concentrations in seminal plasma were measured using the ELISA method. Additionally, we assessed the in vitro effect of OPN on sperm motility parameters in AZS patients and controls.

Results: Significantly lower OPN concentrations were observed in the seminal plasma of infertile men with AZS compared to healthy controls (P<0.0001). OPN levels discriminated between the groups, with an area under the curve of 0.793. Additionally, in vitro OPN treatment significantly improved sperm motility in the AZS group, enhancing progressive and total motility, as well as kinematic parameters in a concentration-dependent manner.

Conclusions: This study established a link between OPN level and sperm motility in infertile individuals with AZS, suggesting the potential of OPN as a biomarker for AZS and as a supplement for assisted reproductive techniques.

Keywords: asthenozoospermia; male infertility; osteopontin; seminal plasma; sperm motility.

Figure 1

OPN concentration in the seminal plasma of infertile men with AZS (n=78) compared to the fertile men (n=80). (A) Scatter plots of OPN concentration in the seminal plasma of infertile men with AZS patients and fertile group using ELISA method. Data are presented as mean ± SEM; ∗∗∗∗P < 0.0001. (B) ROC curves assessing the discriminative capability of OPN levels between infertile men with AZS and healthy fertile men, showing significant discriminative power with an AUC value of 0.793 (95% Confidence Interval, 0.724–0.863).

Figure 2

Correlations between seminal plasma OPN levels and sperm motility. Significant correlations were observed between OPN concentration and (A) progressive motility (r=0.7, P<0.01), (B) total motility (r=0.67, P<0.01), (C) SPR (r=0.43, P<0.01), (D) VCL (r=0.59, P<0.001), (E) VSL (r=0.62, P<0.001) and (F) VAP (r=0.62, P<0.001) based on Spearman’s correlation analysis. Red lines indicate linear regression fits.

Figure 3

Spearman’s correlations between the seminal OPN level and the sperm parameters. The values of the color bar reflect the correlation coefficients between the seminal OPN level and the sperm parameters. PM, progressive motility; TM, total motility; SPR, super-progressive ratio; TN, total number; CC, concentration; VCL, curvilinear velocity; VSL, straight line velocity; VAP, average path velocity; NM, normal morphology. *P< 0.05, **P< 0.01, ***P< 0.001.

Figure 4

Concentration-dependent activation of human sperm motility by OPN over 1 hour in vitro. Following 1 hour of exposure to varying concentrations of OPN, there was a significant enhancement in (A) progressive motility, (B) total motility, (C) SPR, (D) VCL, (E) VSL, and (F) VAP in the AZS group. Data are presented as mean ± SD; Asterisks indicate statistical significance relative to the blank control (BSA group): ∗∗∗P < 0.001, ∗∗∗∗P < 0.0001,.

Figure 5

Concentration-dependent activation of human sperm motility by OPN over 2-hour in vitro. Notable increases were observed in (A) progressive motility, (B) total motility, (C) SPR, (D) VCL, (E) VSL, and (F) VAP within the AZS group, with effects being concentration-dependent and most pronounced at 0.1μg/mL OPN. Data are presented as mean ± SD; Asterisks indicate statistical significance relative to the blank control (BSA group): ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001, ∗∗∗∗P<0.0001.

Figure 6

Effects of OPN on sperm motility parameters over different incubation time. Enhancements were significantly more pronounced after 1 hour of incubation than after 2 hours across various parameters: (A) progressive motility, (B) total motility, (C) SPR, (D) VCL, (E) VSL, and (F) VAP. Data are presented as mean ± SD; Asterisks indicate statistical significance relative to the baseline group: ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001.