Effect of sperm treatment with lysolecithin on in vitro outcomes of equine intracytoplasmic sperm injection.

This research paper studied the effects of treating horse sperm with lysolecithin, during Intracytoplasmic sperm injection (ICSI), on the sperm’s ability to activate the oocyte and the stability of the plasma and acrosomal membranes. The study found that lysolecithin treatment is unnecessary for ICSI in horse embryos.

Research Context and Objective

• The focus of the research is Intracytoplasmic sperm injection (ICSI), a technique commonly used in horses both clinically and commercially. However, there is room for improving the efficiency of this process.
• The researchers set out to test their hypothesis that destabilizing the plasma and acrosomal membranes in the sperm before injection could enhance the developmental potential of equine zygotes formed through ICSI.
• To determine this, they evaluated the effects of treating sperm with lysolecithin, a compound thought to have the capacity to influence these membranes and the sperm’s oocyte activation ability.

Methodology and Findings

• The study followed a two-step process: first conducting a heterologous ICSI on bovine oocytes and then replicating this process with equine oocytes.
• In both procedures, the sperm were treated with various concentrations of lysolecithin, with the plasma membrane, acrosomal membrane, and DNA integrity being assessed via flow cytometry.
• The findings demonstrated that a 0.08% concentration of lysolecithin destabilized the membranes of all observed sperm, and impacted DNA integrity within a range consistent with the species norms (8-30%).
• However, the lysolecithin-treated sperm showed a reduced ability to activate the oocyte in the heterologous ICSI assay. As a result, chemical oocyte activation had to be used following lysolecithin-treated sperm injection during equine ICSI. The subsequent development rate was found to be similar to control groups, both with and without exogenous activation.

Conclusion and Implications

• The results led the researchers to conclude that pre-treatment with lysolecithin is not a necessity when carrying out ICSI to produce equine embryos in vitro.
• The research provides valuable insights about the influences on ICSI efficiency in horses, aiding the further refinement and optimization of the process.