The molecular basis of the injurious actions of non-steroidal anti-inflammatory drugs (NSAIDs) on the gastrointestinal (GI) tract is only partly understood. In this study we have obtained evidence, employing both in vitro and in vivo systems, that five NSAIDs have the ability to form a chemical association with zwitterionic phospholipids. Since this same class of phospholipids line the luminal aspects of the mucus gel layer to provide it with non-wettable properties, this intermolecular association may be the mechanism by which NSAIDs attenuate the hydrophobic barrier properties of the upper GI tract. Preassociating a number of NSAIDs with exogenous zwitterionic phospholipids prevented this increase in surface wettability of the mucus gel layer and protected rats against the injurious GI side-effects of these drugs, while enhancing their lipid permeability, antipyretic and anti-inflammatory activity.
Abstract. The present study was conducted to determine the criteria for selecting good quality embryos on Day-2 postinsemination and at the blastocyst stage. Bovine oocytes were matured, fertilized and cultured in vitro. First, Day-2 embryos were classified based on the number of blastomeres into 2-cell, 3-to 4-cell, 5-to 8-cell and >8-cell stage embryos; chromosome samples were then prepared. In the second experiment, the Day-2 embryos classified according to the number of blastomeres were cultured separately for an additional 6 days (Day 8). The resultant Day-8 blastocysts from each group of Day-2 embryos were classified into the following 3 grades based on morphology and diameter: Grade A, hatched and hatching blastocysts; Grade B, expanded blastocysts; and Grade C, unexpanded blastocysts. Chromosome samples were then prepared. The 5-to 8-cell stage Day-2 embryos had the lowest incidence of chromosomal abnormalities (13.5%, P<0.05) and the highest development rate to blastocysts (59.2%, P<0.05). Furthermore, the blastocysts derived from the 5-to 8-cell stage embryos had the largest mean number of cells (102.8 ± 42.4, P<0.05), largest number of metaphases per blastocyst (9.5 ± 4.8, P<0.05) and lowest incidence of chromosomal abnormalities (24.6%, P<0.05). The Grade A blastocysts had the largest mean number of cells (136.6 ± 33.4, P<0.05), a large number of metaphases per blastocyst (11.9 ± 5.5, P<0.05) and a low incidence of severe chromosomal abnormalities (17.3%). The results showed that, at Day 2, the 5-to 8-cell stage embryos were of better quality since they had the lowest incidence of chromosomal abnormalities and the highest blastocyst rate and the resultant blastocysts had the largest number of cells and lowest incidence of chromosomal abnormalities. In particular, selection of Grade A blastocysts can improve the development rate to term.
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