Equine Spermatozoa Selection by Magnetic Activation for Use in Assisted Reproduction.

This research is into the use of magnetic activation to select high-quality sperm from equine semen, for use in assisted reproduction. The method was compared to one using density gradient centrifugation and showed promising results for decreasing the number of abnormal or damaged sperm cells.

Study Design and Methods

• The semen of 10 stallions was collected using an artificial vagina technique. This method is a common way of obtaining semen samples in a non-invasive manner.
• The team analyzed the collected semen on four counts: (1) fresh semen; (2) processed via density gradient centrifugation (DGC); (3) processed using magnetic activation separation (MASS) to isolate nonapoptotic (healthy) sperm cells; (4) processed using MASS to separate apoptotic (dying or dead) sperm cells.
• Each sample was evaluated for sperm motility (how well they move), concentration (how many sperm are present), morphology (what the sperm look like), and a supravital test, which helps identify dead cells.
• The DGC method used a specific gradient of Percoll and a centrifuge speed of 900 G for 5 minutes. The semen pellet obtained after centrifugation was then diluted in HEPES.
• In the MASS technique, sperm cells were diluted and then centrifuged at a lower speed compared to DGC. The resulting pellet was resuspended with nanoparticle-bound annexin V, a protein that binds to certain phospholipids that become exposed on the outside of cells undergoing apoptosis. After incubation, the samples were filtered through a magnetic separation column, allowing the separation of apoptotic and nonapoptotic fractions.

Results and Conclusions

• The researchers found that both DGC and MASS were effective methods of reducing sperm abnormality, with an overall over 40% abnormality rate dropped to around 16% using DGC, and 24% using MASS.
• The number of cells with intact membranes was found to be about 50% lower in the apoptotic fraction than in the other samples. This result is expected as dying or dead cells often have disrupted membranes.
• The team concluded that the nanotechnological method of magnetic activation to select sperm is efficient for producing high-quality semen samples for assisted reproduction procedures. This could have far-reaching implications in the field of animal breeding, improving the success rates of these procedures and ultimately leading to healthier offspring.