The role of deoxyribonuclease I in amniotic fluid during pregnancy and labour.
The purpose of this study was to detect the presence, and determine the normal values and the significance of DNase I in the amniotic fluid and in human placentas. Fifty-one pregnant women at 16-22 weeks of gestation and 89 women in spontaneous labour at term were recruited to the study. DNase I activity was measured in amniotic fluid and cytoplasmic extracts from the fetal portion of placentas by using a spectrophotometric technique (DNA precipitation assay) and nucleic acid electrophoresis, following degradation of the DNA by the enzyme. DNase I activity was undetectable in the placental cytoplasmic extracts. In the second trimester of pregnancy DNase I activity was detectable in amniotic fluid (2.3+/-0.64x10(5) U/l). During labour DNase I activity was also detectable, but reduced levels were observed in the presence of clear amniotic fluid, compared to second trimester levels, (1.9+/-0.44x10(5) U/l, P<0.001), whereas higher levels were found in the presence of meconium-stained amniotic fluid compared to both second trimester and clear amniotic fluid at labour (11.4+/-4.1x10(5) U/l, P<0.001 and P<0.001, respectively). Three out of 17 fetuses with meconium-stained amniotic fluid (18%) developed perinatal infection. In conclusion, the detection of DNase I activity in the amniotic fluid of second and third trimester indicates a physiological role in human pregnancy. DNase I activity normally decreases at term, compared to second trimester levels, but increases significantly in the presence of meconium.
Lolis
D E
DE
Department of Obstetrics and Gynaecology, University Hospital of Ioannina, Greece.
Kalantaridou
S N
SN
Stefos
T
T
Makrydimas
G
G
Georgiou
I
I
D000653:Amniotic Fluid / Q000201:enzymology*; D004247:DNA / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D005260:Female; D005865:Gestational Age; D006801:Humans; D007743:Labor, Obstetric / Q000378:metabolism*; D008470:Meconium; D010920:Placenta / Q000201:enzymology; D011247:Pregnancy / Q000378:metabolism*; D012016:Reference Values
D004247:DNA; D003850:Deoxyribonuclease I