Initial characterization of an in vitro rabbit sperm activation assay.
Brown-DB; Sawyer-DE; Maeker-BJ; Breitenstein-MJ; Hillman-GR; Schrader-SM
Toxicologist 1997 Mar; 36(1)(Part 2):360
Previous studies have shown that both human and rat sperm nuclei can be activated in vitro using a cytoplasmic extract from Xenopus laevis frog eggs. Activated nuclei undergo chromatin decondensation, DNA synthesis, and recondensation (human only). To complement these systems, we are developing a rabbit sperm activation assay. Lysolecithin-permeabilized rabbit sperm were incubated in 3H-TTP-spiked X. laevis frog egg extract. Decondensation was assessed visually using phase-contrast microscopy and quantitatively using an image analysis system. DNA synthesis was assessed using autoradiography. Ejaculates from three different rabbits were used for these studies. Activated sperm nuclei from two of the rabbits decondensed to about 11 times their original size at a rate of approximately 175 U/min. (arbitrary units). Interestingly, multiple ejaculates from one rabbit repeatedly displayed attenuated decondensation (7.5X size increase and 114 U/min.); the reason for this is being investigated. Greater than 95% of the activated sperm nuclei consistently replicate DNA. We plan to use the rabbit sperm activation assay to perform in vivo toxicology studies on toxic agents known to bind sperm chromatin. This assay will complement the rat sperm activation assay and allow for multispecies toxicology studies evaluating sperm nuclear activation as an endpoint.
Toxic-materials; Toxins; Exposure-assessment; Exposure-levels; Exposure-limits; Reproductive-effects; Reproductive-hazards; Reproductive-system; Reproductive-system-disorders; Animal-studies; Animals; Laboratory-animals
The Toxicologist. Society of Toxicology 36th Annual Meeting, March 9-13, 2006, Cincinnati, Ohio