Morphohistometric Investigation and bcl-2 Expression in the Placenta of Chromosomally Abnormal Pregnancy

ABSTRACT

To evaluate the significance of placental histology, a collaborative histological and cytogenetic study was performed on the products of 88 spontaneous abortions, and subsequently bcl-2 immunostaining was performed on 62 cases. The morphometric parameters included were DCIRCLE, FORMSHAPE, CPRATIO, and the expression of bcl-2 immunostainig was graded in four categories (I to IV). The results were as follows 1) 40% (n=35) were chromosomally abnormal trisomies predominated (57%, n=20) and was followed by triploidy (14%, n=5), double trisomy (6%, n=2), monosomy X (6%, n=2), inversion (9) (6%, n=2). 2) mean of DCIRCLE in chromosomally abnormal pregnancy was 40 micrometer larger than that in chromosomally normal pregnancy (p=0.012, one side t-test), while no difference was found in FORMSHAPE and CPRATIO between chromosomally abnormal and normal pregnancy. 3) bcl-2 expression was found in syncytiotrophoblast and cytotrophoblast. bcl-2 expression was weaker in chromosomally abnormal pregnancy with intensity I and II of 59% than chromosomally normal pregnancy with intensity I and II of 24%. 4) In comparison bcl-2 expression with DCIRCLE, in chromosomally normal abortion one (10%) in I & II and one (3%) in III & IV showed large DCIRCLE (above 360 micrometer), while 11 (85%) in I & II and 3 (33%) in III & IV in chromosomally abnormal pregnancy. It would mean that bcl-2 protein is necessary in preservation of pregnancy and placental morphology. Abnormal villous diameter and weak bcl-2 expression may be suggestive of chromosomal anomaly. Besides other histologic parameters, application of bcl-2 immunostaining and morphometric analysis probably give more sensitive and specific results in identifying chromosomally abnormal abortion.