Related Experiment Videos
A human seminal plasma protein blocks the motility of human spermatozoa
1Urology Research Laboratory, Royal Victoria Hospital, Montreal, Quebec, Canada.
Abstract:
An inhibitor of the motility of demembranated spermatozoa has been shown to be present in human seminal plasma. This seminal plasma motility inhibitor (SPMI) was purified to apparent homogeneity and tested on intact human spermatozoa. Motility parameters of spermatozoa incubated with the sperm motility inhibitor were evaluated with the video automated Cell Soft system. SPMI decreased the percentage of motile spermatozoa in a dose-dependent manner and motility was completely blocked in the presence of 1600 units/ml. Sperm velocity and beat/cross frequency showed a similar progressive decrease as the inhibitor was augmented. However, linearity was essentially not affected. The effects of SPMI on the percentage of motile spermatozoa increased with the time of contact between the inhibitor and spermatozoa. After 120 min., the IC50 was 35% lower than that observed at five min. The presence of seminal plasma did not prevent the inhibitory effects of the seminal plasma factor on sperm motility parameters. On the contrary, a potentiating effects was observed. The data suggest that the SPMI could play a significant role in cases of infertility caused by asthenospermia.
Insights
A newly identified seminal plasma motility inhibitor (SPMI) significantly reduces sperm motility and velocity in a dose- and time-dependent manner, potentially contributing to asthenospermia infertility.
Area of Science:
- Reproductive Biology
- Biochemistry
- Andrology
Background:
- Human seminal plasma contains factors influencing sperm function.
- Sperm motility is crucial for natural fertilization.
- Asthenospermia, characterized by poor sperm motility, is a common cause of male infertility.
Purpose of the Study:
- To purify and characterize a motility inhibitor from human seminal plasma.
- To evaluate the effects of this inhibitor on intact human spermatozoa motility.
- To investigate the potential role of this inhibitor in asthenospermia.
Main Methods:
- Purification of seminal plasma motility inhibitor (SPMI) to homogeneity.
- Incubation of intact human spermatozoa with purified SPMI.
- Assessment of sperm motility parameters using the video automated Cell Soft system.
- Dose-response and time-course analyses of SPMI effects.
Main Results:
- SPMI significantly decreased the percentage of motile spermatozoa in a dose-dependent manner, with complete blockage at 1600 units/ml.
- Sperm velocity and beat/cross frequency were progressively reduced by SPMI, while linearity remained unaffected.
- The inhibitory effect of SPMI on sperm motility increased with incubation time, showing a lower IC50 after 120 minutes compared to 5 minutes.
- Seminal plasma potentiated, rather than inhibited, the effects of SPMI on sperm motility.
Conclusions:
- A potent inhibitor of sperm motility (SPMI) exists in human seminal plasma.
- SPMI affects key sperm motility parameters, including velocity and beat/cross frequency.
- SPMI may play a significant role in the pathophysiology of asthenospermia and related infertility.