Development and validation of portable hemogasometer for bovine blood and allantois fluid analysis of pO2, pH, Na+, K+ e Ca++

Abstract

The ability to produce viable products by SCNT provides remarkable new perspectives in animal production and science. Bovine SCNT cloning is a prominent new technology, however still presents very low efficiency and high costs. Animals elected to have progeny multiplied by SCNT cloning are those presenting high performance in many different aspects, endangered, or incapable to produce its own gametes. Efficiency in terms of live birth in SCNT cloning in bovines is around 9% after ET. The costs to produce the cloned blastocyst are elevated and after ET 91% of them will die. In conjunction with the losses, costs associated with recipient synchronization and maintenance must be considered, representing a costly loss. The majority of the pregnancy losses occur during early pregnancy, until Day 60. The sequence of events occurring during these two months is key to development. During this time, endometrial vascular stimulation guarantees an adequate uterine environment for embryo survival, maternal recognition of pregnancy, implantation, placentation, and placentome development. After that, uterine tissue and vascular remodeling will continue throughout pregnancy in parallel to fetal development as requirements increase. During all losses, the observed macroscopic pathologies are clearly related to vascular disturbances. Our previous work in mares and cows clearly demonstrated the efficiency and reliability of the Doppler ultrasound technique to assess uterine and conceptus vascular changes during early pregnancy.The Young Investigator Project aims to study deeply late pregnancy in bovine SCNT cloned embryo pregnancies. Pregnancies of SCNT clones are associated with large offspring syndrome (or large placenta syndrome), hydrallantois, placentomegaly, fetal edema (head, umbilical cord, anasarca, and others). In addition, this period coincides with an increase in fetal growth rate when the placenta is challenged more and more to supply the fetal demands until term. In SCNT pregnancies, probably the impaired placenta is not capable of responding, resulting in abnormal or inadequate morphological development. Expression of factors related to placenta vascular development and remodeling is probably unbalanced and uncontrolled, being the cause of the observed pathologies. This physiopathology described in clones suggests some similarities with preeclampsia syndrome in women. Preeclampsia occurs in an estimated 3-5% of births, and is a leading cause of both fetal and maternal morbidity and mortality worldwide.The importance of this Scientific Iniciation Project is to develop and validate the use of the portable hemogasometer equipment instead of the tradicional methods of analysis of blood. This will permit one unique procedure to analize O2, pH, Na+, K+ and Ca++ in a fast and simple way, helping the experiments in the field to study placentary vascular remodeling. The hemogasometer is calibrated to analize blood and it will be also tested in this experiment to analize allantoic fluid. (AU)