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Mtango, N.

Publications and source records attributed to Mtango, N..

2 recordsLinked to original sources
bioRxiv2025

High-Yield Induced Ovulation in Adult Fat-Tailed Dunnarts by PMSG Treatment Combined with Estrus Synchronization

The fat-tailed dunnart, Sminthopsis crassicaudata, is an emerging laboratory-based marsupial model for research on comparative biology, reproduction and conservation. In females, the reproductive cycle lasts 31 days and approximately 10 oocytes are ovulated per cycle. Assisted reproductive technologies (ART) play a crucial role in marsupial conservation, but developing protocols to harvest large numbers of oocytes remains a key challenge. Specifically, producing sufficient mature metaphase II (MII) oocytes in dunnarts continues to be difficult. Ovarian follicle stimulation is common practice to achieve superovulation in many species and typically requires treatment of prepubertal female animals to avoid the impacts of endogenous hormone cycling. Alternatively, adult females can be stimulated during the intermediate or follicular phase. In this study, we aimed to develop a high-yield induced-ovulation protocol to collect higher number of MII oocytes from adult, cycling, female dunnarts. We first synchronized the female dunnart reproductive cycles using luteinizing hormone-releasing hormone (LHRH). The reproductive cycles were monitored by examining cytology of vaginal lavage samples. After administering four LHRH injections given at three-day intervals, 88.9% (n=36) of the adult female dunnarts responded to the treatment, with their estrous cycles synchronized at the diestrous stage. We then induced ovarian follicle development through two PMSG injections over 6 days, followed by hCG administration to trigger ovulation. By combining estrous cycle synchronization with PMSG stimulation, we achieved 77.8% (n=36) ovulation success and obtained an average of 20.1{+/-}9.1 (n=28) MII oocytes per adult dunnart. These data demonstrated that estrous cycle synchronization followed by the PMSG-hCG treatment yields consistent, highly efficient induced-ovulation in adult dunnarts. This approach of combining estrus synchronization and follicle stimulation to produce sufficient MII oocytes for ART purpose could be applied to other valuable marsupial species to support conservation efforts. Summary SentenceSuperovulation and robust production of mature MII oocytes can be induced by 10-day estrus synchronization using LHRH followed by 6-day PMSG stimulation of follicle growth in adult fat-tailed dunnarts, a marsupial species. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/671172v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@14c6685org.highwire.dtl.DTLVardef@decf75org.highwire.dtl.DTLVardef@64330org.highwire.dtl.DTLVardef@12538a4_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗
bioRxiv2025

Generation and Assessment of High-Quality Fat-Tailed Dunnart Oocytes Following Superovulation in Prepubertal Animals

The fat-tailed dunnart, Sminthopsis crassicaudata, is a mouse-sized, polyovular, solitary dasyurid marsupial found in central and southern Australia. With the establishment of a chromosome-scale genome assembly, induced pluripotent stem cells, and targeted genetic editing, the dunnart is emerging as the laboratory marsupial model for comparative developmental, reproductive and conservation biology. The development of assisted reproductive technologies (ART) are critical to achieving these goals in this species. ART requires a large number of mature oocytes which are typically collected through stimulated and synchronised female reproductive cycles. While protocols for induced-ovulation or superovulation are standard in many placental mammals, there are no methods to date designed for marsupials. In the present study, prepubertal dunnarts were stimulated with pregnant mare serum gonadotrophin and human chronic gonadotrophin across 6 different treatment regimens. Our best regimen resulted in over 70% of prepubertal dunnarts ovulating with 82% normal oocytes. When the primed females were mated with stud males, 4-cell stage embryos were collected 48 h post-hCG administration. At around 96 h post-hCG, 50% (n=8) and 78% (n=9) of the embryos developed to blastocysts. Our results demonstrated successful stimulation of ovulation and mature oocyte collection in prepubertal dunnarts. Furthermore, we confirmed developmental competence of the induced ovulated oocytes through to at least the blastocyst stage. These findings represent the first robust hormonal regimen for predictable oocyte generation in any marsupial and will significantly contribute to the use of the dunnart in developmental and conservation biology.

developmental biology↗