The incidence of apoptosis after IVF with morphologically abnormal bovine spermatozoa

• Published in: Theriogenology 2005-10, Vol.64 (6), p.1404-1421
• Main Authors: Walters, A.H., Saacke, R.G., Pearson, R.E., Gwazdauskas, F.C.
• Format: Article
• Language: English
• Subjects: Abnormal spermatozoa; Animals; Apoptosis; bulls; Caspase intensity; Caspases - metabolism; cattle; Cattle - embryology; Cattle - physiology; Embryo development; Embryo Implantation - physiology; Embryonic Development - physiology; Female; Fertilization in Vitro - veterinary; In Situ Nick-End Labeling - veterinary; in vitro fertilization; Incidence; Male; Pregnancy; Scrotal insult; Scrotum - injuries; Scrotum - physiology; Spermatozoa - abnormalities; TUNEL
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2005.03.011

Normal embryonic development depends on the maintenance of a population of normal healthy cells within each embryo. The aim of this study was to use a combination of apoptotic measures to assess differences in embryo quality after IVF with semen samples with high percentages of abnormal spermatozoa. Semen samples were obtained and cryopreserved from four Holstein bulls before (5 day prior) and after (2 week-post-insult; 2 week-PI and day 20; 3 week-PI) a scrotal insulation period of 48 h (day 0). The swim-up sperm separation method was used. The post-thaw morphology revealed a decrease ( P < 0.01) in the percentages of normal spermatozoa in the 3 week-PI samples in comparison with the pre-insult samples for Bulls I and III (74–22.3 and 67.7–0.5%, respectively). The percentage of vacuolated spermatozoa increased significantly for Bull II. After 18 h of sperm-oocyte co-incubation, zygotes were cultured and subpopulations were removed from culture at day 8 and subjected to either the TUNEL or caspase assay. On day 8, caspase intensity increased significantly for both Bull I (217 ± 147) and Bull III (229 ± 98) for the 3 week-PI embryo groups compared to the equivalent embryo groups for Bull II (98 ± 115) and Bull IV (90 ± 111). In conclusion, the inability to consistently measure apoptosis with TUNEL alone complicated the assessment of differences in embryo quality. Thus, it is uncertain exactly when during early pre-implantation development the differences in embryo quality are first manifest. Despite discrepancies, our results clearly indicated a difference in the embryo quality between embryos obtained after IVF with semen samples from bulls that had an intense response to scrotal insulation.