The cold shock of spermatozoa is associated with oxidative stress induced by reactive oxygen species. This study was conducted to evaluate the toxicity of natural antioxidant green tea extract (GTE) in lactose-egg yolk (LEY) extender during boar sperm cooling prior to freezing. Spermatozoa were cooled to 5℃ for 3 h in LEY extender containing 0 (control), 1, 10, 100 or 1,000 mg/l of GTE, re-suspended with LEY-glycerol-Equex extender and cooled at 5℃ for 30 min. Sperm progressive motility, viability and phosphatidylserine (PS) translocation were evaluated. PS translocation was assayed by flow cytometry using Annexin V-FITC apoptosis detection kit. The sperm function including progressive motility, viability and PS translocation was not significantly different regardless of GTE concentrations (P>0.05). In conclusion, this study demonstrated non-toxicity of GTE supplement in LEY extender during sperm cooling.

INTRODUCTION
 MATERIALS AND METHODS
  1. Chemicals
  2. Collection of Semen
  3. Sperm Cooling
  4. Sperm Motility
  5. Sperm Viability
  6. Phosphatidylserine (PS) Translocation
  7. Statistical Analyses
 RESULTS
 DISCUSSION
 REFERENCES

• Sang-Hyoun Park(Department of Theriogenology and Reproductive Biotechnology,College of Veterinary Medicine and Bio-safety Research Institute, Chonbuk National University)
• Il-Jeoung Yu(Department of Theriogenology and Reproductive Biotechnology College of Veterinary Medicine and Bio-safety Research Institute, Chonbuk National University) Correspondence