Comparison of Apoptosis and Bcl-2 Expression in Normal Pregnancy, Pregnancy Induced Hypertension and Intrauterine Growth Restriction

Kim, Heung Seo; Noh, Heung Tae; Rhee, Yun Ee; Song, Kyou Sang

Abstract

OBJECTIVE
The purpose of this study was to investigate the incidence of apoptosis and expression of bcl-2 in the placenta of normal pregnancy, Pregnancy Induced Hypertension, and Intrauterine Growth Restriction.
METHODS
Placenta samples were collected from 15 cases of normal full-term pregnancies, 15 cases of second trimester pregnancies, 17 cases of Pregnancy Induced Hypertension, and 13 cases of Intrauterine Growth Restriction. Hematoxylin and eosin staining and TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate marker nick end-labeling) staining were used to quantify the incidence of apoptosis and the electron microscopy was used to confirm it. Expression of bcl-2 was confirmed by using immunohistochemical stain in relation to apoptosis.
RESULTS
1. In TUNEL staining, quantification of apoptosis was 1.05 in 2nd trimester (n=15), 3.65 in pregnancy induced hypertensive pregnancy (n=17), 2.92 in intrauterine growth restrictive pregnancy (n=13) and 1.93 in normal full-term pregnancy (n=15). The incidence of apoptosis was significantly higher in placental tissues from full-term pregnancies than second trimester pregnancies (p<0.05, t test), and higher in pregnancy induced hypertensive pregnancy and in intrauterine growth restrictive pregnancy than in normal full-term pregnancy (p<0.05, t test). 2. Bcl-2 expression was significantly higher in placental tissues from second trimester pregnancies than full-term pregnancies (p<0.05 t test). But, there was no statistically significant difference between pregnancy induced hypertension and normal full-term pregnancy (p>0.05, t test), and between intrauterine growth restriction and normal full-term pregnancy (p>0.05, Mann-Whitney U test).
CONCLUSION
These data suggest that apoptosis increases with gestational age, and in pathophysiologic states such as pregnancy induced hypertension and intrauterine growth restriction, and that bcl-2 expression is lower with gestational age.