Bull sperm as a potential model system for cytotoxicity testing in vitro.

Area of Science:

• Reproductive Biology
• Toxicology
• Biochemistry

Background:

• Frozen/thawed bovine sperm offer a practical model for assessing chemical toxicity.
• Established endpoints include progressive motility, adenosine triphosphate (ATP) content, and cell death.

Purpose of the Study:

• To evaluate frozen/thawed bovine sperm as a model system for cytotoxicity.
• To compare different endpoints (motility, ATP, cell death) for toxicant assessment.

Main Methods:

• Sperm motility, ATP content, and cell death were measured after exposure to toxicants.
• Toxicants included nonylphenoxypolyethoxyethanol (nonoxynol-9), Gynol II, and dl-propranolol.
• Measurements were taken within a 30-minute window after initial 15-minute stabilization.

Main Results:

• ATP content was lower in extender compared to the final diluent (Eagle's MEM with 5% foetal calf serum).
• Nonoxynol-9 and Gynol II showed similar effects on ATP and cell death, but Gynol II impacted motility more.
• dl-Propranolol was less toxic than nonoxynol-9 based on ATP content.

Conclusions:

• Sperm ATP content measurement is the preferred method for cytotoxicity assessment due to automation and mechanistic information.
• Excipients in Gynol II appeared to reduce the effectiveness of nonoxynol-9.
• No membrane ultrastructural damage was observed with scanning electron microscopy at 75 µg/ml nonoxynol-9.