Culture of Preimplantation Rabbit Embryos.

It is surprising that so little attention is currently given to in vitro culture of preimplantation rabbit embryos, even though the rabbit is the only laboratory animal in which there is very considerable embryo growth before implantation, resulting in a 300-fold increase in protein content of embryonic cells during the preimplantation period and the formation of more than a 100,000 cells in the blastocyst. This growth pattern explains why blastocyst formation in vitro has an absolute requirement for amino acids, and vitamins, particularly inositol, are esssential for blastocyst growth. A semi-defined medium supplemented with 1.5% BSA (variously known as BSM II or modified F10) was developed at Cornell University at the end of the 1960s and allowed the systematic investigation of the requirements for development of 1-cell rabbit embryos to blastocysts. However, the requirements for in vitro blastocyst growth comparable to in vivo growth still remain an unsolved problem. Citrate, often found as a contaminant in serum albumin, may have an essential role in rabbit blastocyst growth, which would fit in with its role in the development of serum-free media for culture of various types of mammalian cells.A comprehensive account of the methodology is given to enable a researcher with experience culturing embryos of a different species to work on the rabbit embryo. This account covers medium preparation, hormonal stimulation of superovulation, natural breeding/artificial insemination, and collection of embryos of different stages from 1-cell to blastocyst either after euthanasia or under anesthesia. Peculiarities of the rabbit embryo such as the presence of the mucoprotein coat and its effects on behavior of cultured and transferred embryos are described. Suggestions are made for future avenues of research.

Morphological and hormonal changes after superovulation in cows treated with Neutra-PMSG.

Morphological changes in ovaries and hormonal changes as well as changes in Na, K, Ca, Mg, and P blood plasma levels were observed after superovulation induced by the administration of PMSG and the neutralization of this hormone with monoclonal antibodies Neutra-PMSG administered either 72 or 108 h later. The introduction of Neutra-PMSG 108 h after PMSG injection clearly decreases the number of surviving non-ovulated follicles with a diameter > 10 mm (1.7 +/- 0.8 vesicle in an individual cow on the average) in comparison to the group without Neutra-PMSG (19.4 +/- 9.5). The efficiency of ovulation in the group treated with Neutra-PMSG in the 108th h of the experiment (8.2 +/- 4.6 corpora lutea per cow on the average), did not differ statistically from the group treated with PMSG only (12.4 +/- 10.6). Early administration of Neutra-PMSG (72h), totally inhibits superovulation. Observations showed, that injection of Neutra-PMSG in the 108th h, caused a considerable decrease in the estradiol level, beginning with the 120th h of the experiment. Determination of the progesterone blood plasma level reflects the number of corpora lutea and can be helpful in evaluating the effects of superovulation. Superovulation did not effect the level of Na, K, Ca, Mg, and P in the blood plasma.