Effects of exposure to tobacco smoke in pregnancies complicted by oligohydramnios and premature rupture of the membranes. II. Activity of brush border enzymes in human amniotic fluid

The aim of the present study was to assess the activity of membrane enzymes: alanine aminopeptidase (AAP), gamma-glutamyltransferase (GGT) and trehalase in amniotic fluid of women who smoke cigarettes during pregnancy complicated by idiopathic oligohydramnios or premature rupture of the membranes (PROM). The enzyme activity was measured between 22 and 31 (group A) and between 32 and 39 (group B) weeks of gestation. In the women of group A with idiopathic oligohydramnios, AAP activity was five times higher than in PROM women. AAP activity was declining with the progression of gestation, and in the B group women with oligohydramnios, it was over eight times lower than in group A. A threefold increase in GGT activity was found in women of group A with oligohydramnios as compared to women of group A with PROM. No statistically significant differences in trehalase activity were found in amniotic fluid of women with oligohydramnios and PROM, AAP, GGT and trehalase activity in women with idiopathic oligohydramnios correlated with the cadmium ion concentration, and AAP and GGT activity with the lead ion concentration in amniotic fluid which confirms toxical properties of these heavy metals present in cigarette smoke. It has already been confirmed that measurements of the brush border enzyme activity in amniotic fluid are very useful in prenatal diagnosis and detection of the placenta disorders.

[Activity of N-b-D-acetylglucosaminidase molecular forms in amniotic fluid of tobacco smoking pregnant women with oligohydramnios or premature rupture of the membrane complications]

OBJECTIVES

Morphological lesions in placenta and changed metal distribution through placenta, which were observed in pregnancy exposed to tobacco smoke, could cause alternations in lysosomal enzymes secretion to amniotic fluid.

DESIGN

Assessment of total activity and molecular forms of N-beta-D-acetylglucosaminidase in amniotic fluid in pregnancy with oligohydramnios or PROM.

MATERIALS AND METHODS

The materials for studies were amniotic fluids collected from pregnancy with oligohydramnios and from pregnancy with PROM. Determination of N-beta-D-acetylglucosaminidase activity was performed with use of sodium salt of 3-crezolosulfthaleinyl-N-beta-D-acetylglucosamide as a substrate (test Boehringer, Niemcy). Creatinine was determined by kinetic method (test of Analco-GBG firm). Protein was determine by Bredford method. NAG-B was assessed after previous thermal NAG-A inactivation in 56 degrees C, for 2 hours and the difference between activity of total form and termostabile form of NAG were assessed. The microsomal and cytosol fractions were separated by ultracentrifugation.

RESULTS AND CONCLUSIONS

The statistically significant growth of NAG activity in amniotic fluid in pregnant with oligohydramnios was observed. The cytosol form took over 90% of whole activity. The activity of NAG microsomal fraction was lower in amniotic fluid in women with PROM diagnosis. The positive coleration between NAG-A activity and the Pb level was observed in this group of women as well. In the second group of women with oligohydramnios, the positive coleration between NAG and Cd level, NAG-A and level, NAG-B and Pb level were demonstrated. Obtained results show on damage of placental and foetal membranes cell structure. It could be caused by metal ions cumulation and releasing of molecular N-beta-D-acetylglucosaminase form to amniotic fluid.