Morphology and cyclooxygenase-2 and renin expression in the kidney of young spontaneously hypertensive rats.

The kidneys play an important role in blood pressure regulation under normal and pathological conditions. We examined the histological changes and expression patterns of cyclooxygenase-2, renin, and (pro)renin receptor (PRR) in the renal cortex of prehypertensive spontaneously hypertensive rats (SHRs) and Wistar Kyoto rats (WKYs). Moreover, blood pressure and plasma urea, creatinine, angiotensin II, and angiotensin (1-7) levels were measured. The results showed that both strains had similar blood pressure and plasma urea and creatinine levels. The glomerular area, basement membrane thickness, collagen fiber content, and arterial wall thickness were greater in SHRs than in WKYs. By immunohistochemistry, cyclooxygenase-2 was localized in the macula densa and renal tubules of both strains. In SHRs, cyclooxygenase-2 was detected in a larger number of tubules, and the cortical expression of cyclooxygenase-2 was also increased. In both strains, PRR and renin were localized in the tubular epithelium and juxtaglomerular cells, respectively. In SHRs, PRR immunolocalization was increased in the glomerulus. The cortical expression of immature renin was markedly increased in SHRs compared to that in WKYs, while renin was significantly decreased. These changes were associated with higher plasma angiotensin II levels and lower plasma angiotensin (1-7) levels in SHRs. The results indicate that the kidneys of SHRs showed morphological changes and variations in cortical expression patterns of PRR, cyclooxygenase-2, and renin before the development of hypertension.

Hyperglycemia-induced mouse trophoblast spreading is mediated by reactive oxygen species.

During embryo implantation, the outer layer of the blastocyst interacts with the endometrium giving rise to the development of the trophoblast cell lineage. The cells in this lineage participate in the penetration of endometrium due to their motility and invasive properties. The mechanisms that regulate the differentiation and invasive ability of these cells are essential for the establishment and maintenance of an efficient exchange between maternal and fetal tissues during pregnancy. In this context, hyperglycemia can induce oxidative stress causing alterations in the placenta. This study evaluated the role of reactive oxygen species (ROS) in the actions of high glucose concentration (HG) on trophoblast spreading and the expression of extracellular proteases in cultured mouse conceptuses. Blastocysts from gestational day 4 (GD4) were cultured until GD7 in HAM-F10 medium and further treated for 48 hr with HG (25 mM glucose) from GD7 to GD9. This treatment induced larger trophoblast outgrowths and increased ROS concentration, which was associated with increased expression levels of urokinase-type plasminogen activator (PLAU), plasminogen activator inhibitor 1 (PAI-1), and matrix metalloproteinase 9 (MMP-9). These effects were prevented by treatment with the non-specific antioxidant N-acetylcysteine (NAC) or apocynin, an inhibitor of NADPH oxidase. Our data suggest that the HG-induced trophoblast spreading and the expression of PLAU, PAI-1, and MMP-9 were mediated by the production of ROS via NADPH oxidase activity. Our results shed light on placental alterations in gestational diabetes mellitus.

Polyamines protect rat embryo in vitro from high glucose-induced developmental delay and dysmorphogenesis.

BACKGROUND: Pregnancy in mammals with diabetes mellitus results in low birth weight, malformations, and intrauterine death. Parenteral application of natural polyamines or their precursor, L-arginine, to diabetic pregnant rats partially prevents the alterations of development caused by diabetes mellitus. This experiment has been designed to understand if this preventive action also occurs in rat whole embryo in culture. MATERIALS AND METHODS: Rat embryos of gestational day 10 were cultured for 24 h in normal medium, high glucose medium, or high glucose medium supplemented with polyamines or L-arginine, and furthermore embryo growth and development were evaluated. RESULTS: L-arginine and putrescine partially prevents the dysmorphogenic effects of high glucose, whereas spermidine and spermine prevent these effects almost completely. CONCLUSIONS: Polyamines directly protect the embryo from the toxic effect of high glucose concentration on growth and development, although the mechanism remains to be elucidated.

Sistemas moleculares en la interacciones celulares: II. Iimplantación embrionaria en mamíferos / Molecular systems in the cellular interactions: II. Embrionary implantation in mammals

En el presente trabajo se revisan los sistemas moleculares de reconocimiento y adhesión celulares que participan en la implantación embrionaria de los mamíferos.En el proceso de implantación embrionaria, las interacciones son compejas, ya que son diversos tipos celulares los involucrados: las células del trofoblasto del embrión interactúan con varias células uterinas y con sus respectivas matrices extracelulare; participando lactosaminoglicanos, integrinas, cadherinas y galactosil transferasas.