A double ovulation protocol for Xenopus laevis produces doubled fertilisation yield and moderately transiently elevated corticosterone levels without loss of egg quality.

Autor: Moss C; Centre for Craniofacial Regeneration and Biology, King's College London, London, United Kingdom., Vacca B; Centre for Craniofacial Regeneration and Biology, King's College London, London, United Kingdom., Arnold J; Department of Biological Sciences, University of Chester, Chester, United Kingdom., Hubens C; Centre for Craniofacial Regeneration and Biology, King's College London, London, United Kingdom., Lynch DM; Centre for Craniofacial Regeneration and Biology, King's College London, London, United Kingdom., Pegge J; Centre for Craniofacial Regeneration and Biology, King's College London, London, United Kingdom., Green MAR; Dept of Economics, University of Oxford, Oxford, United Kingdom., Hosie CA; Department of Biological Sciences, University of Chester, Chester, United Kingdom., Smith TE; Department of Biological Sciences, University of Chester, Chester, United Kingdom., Green JBA; Centre for Craniofacial Regeneration and Biology, King's College London, London, United Kingdom.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2024 Jul 19; Vol. 19 (7), pp. e0299179. Date of Electronic Publication: 2024 Jul 19 (Print Publication: 2024).
DOI: 10.1371/journal.pone.0299179
Abstrakt: The African claw-toed frog, Xenopus laevis, is a well-established laboratory model for the biology of vertebrate oogenesis, fertilisation, and development at embryonic, larval, and metamorphic stages. For ovulation, X. laevis females are usually injected with chorionic gonadotropin, whereupon they lay typically hundreds to thousands of eggs in a day. After being rested for a minimum of three months, animals are re-used. The literature suggests that adult females can lay much larger numbers of eggs in a short period. Here, we compared the standard "single ovulation" protocol with a "double ovulation" protocol, in which females were ovulated, then re-ovulated after seven days and then rested for three months before re-use. We quantified egg number, fertilisation rate (development to cleavage stage), and corticosterone secretion rate as a measure of stress response for the two protocol groups over seven 3-month cycles. We found no differences in egg number-per-ovulation or egg quality between the groups and no long-term changes in any measures over the 21-month trial period. Corticosterone secretion was elevated by ovulation, similarly for the single ovulation as for the first ovulation in the double-ovulation protocol, but more highly for the second ovulation (to a level comparable to that seen following shipment) in the latter. However, both groups exhibited the same baseline secretion rates by the time of the subsequent cycle. Double ovulation is thus transiently more stressful/demanding than single ovulation but within the levels routinely experienced by laboratory X. laevis. Noting that "stress hormone" corticosterone/cortisol secretion is linked to physiological processes, such as ovulation, that are not necessarily harmful to the individual, we suggest that the benefits of a doubling in egg yield-per-cycle per animal without loss of egg quality or signs of acute or long-term harm may outweigh the relatively modest and transient corticosterone elevation we observed. The double ovulation protocol therefore represents a potential new standard practice for promoting the "3Rs" (animal use reduction, refinement and replacement) mission for Xenopus research.
Competing Interests: The authors have declared that no competing interests exist.
(Copyright: © 2024 Moss et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
Databáze: MEDLINE
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