Glucose movement into rat interine fluid

Towards the use of microfluidics for individual embryo culture

Mammalian embryo development is still relatively inefficient in vitro. Much research has been conducted on the chemical environment, or culture medium, surrounding the embryo, but little attention has been given to the actual physical culture environment, which has changed very little over the years. The application of microfluidics to embryo production in vitro is a tantalising approach that may alleviate some of the limits that traditional microdrop culture places on embryo development and research into gamete and embryo physiology. These devices may lead to enhanced in vitro embryo development and quality by more closely mimicking the in vivo environment. Initial work in this area is promising and gives us proof-of-principle that these unique microfluidic systems may indeed be applicable to in vitro culture of gametes and embryos. The present paper reviews the advantages of microfluidics for in vitro embryo production: how the platforms are manufactured, the current uses of microfluidics in assisted reproduction, static v. dynamic culture environments, individual gamete and embryo culture and the future directions of microfluidic application to in vitro embryo production and manipulation. Finally, preliminary data from our laboratory using a new microfluidic well insert for porcine, bovine and murine embryo culture is discussed.

Desensitization of rabbit myometrium to oxytocin and prostaglandin F2 alpha

The desensitizing effects of oxytocin (OT) and prostaglandin F2 alpha (PGF2 alpha) were investigated in the uteri of rabbits. Uterine motility was measured in anesthetized rabbits infused intravenously with either PGF2 alpha (50 micrograms/min) or OT (100 mU/min) alternately. The treatment sequence was saline (30 min), first drug (OT or PGF2 alpha, 90 min), second drug (OT if PGF2 alpha was first drug and vice versa, 90 min), and first drug (repeated) 60 min. Both OT and PGF2 alpha infusions increased motility approximately 200% within 5-10 min. Thereafter, motility decreased linearly to base-line value. Fifty percent desensitization was completed at 35-45 min and 100% at 90 min. A tenfold increase in the infusion rate caused no further increase in motility. However, OT infusion into a PGF2 alpha desensitized uterus (and vice versa) elicited an immediate uterokinetic response. Oxygen consumption and glucose oxidation rate of uterine slices measured at different stages (preinfusion, maximal motility, and desensitized) of uterine motility showed no difference (P greater than 0.05) between the two experimental treatments. It was concluded that either OT or PGF2 alpha infusions specifically desensitized the uterus.

The effect of intrauterine injection of concanavalin A on implantation in mice and rats

Concanavalin A (Con A) binding sites are present on the surface of blastocysts. When Con A was injected into one uterine horn of the mouse on Day 3 or 5 of pregnancy at 50 or 100 micrograms/horn, or given to the rat on Day 6 or 7 at 200 micrograms/horn, implantation and pregnancy was not affected when compared to the contralateral horn treated with vehicle alone. However, when the same amount of Con A was administered to the mouse on Day 4 or to the rat on Day 5, implantation was significantly decreased, all accompanied by the incidence of deciduomata. The deciduogenicity of Con A is dose-dependent. Also Con A did not affect the development of mouse embryos as a normal number of blastocysts was recovered up to the time of implantation. Thus the inhibition of implantation by Con A could be due to (a) the earlier occurrence of decidual cell response and its subsequent interference with implantation and (b) the involvement of specific sugar groups in implantation.