The Effect of Low Molecular Weight Heparins on Placentation: A Rat Model Study

Low molecular weight heparins (LMWHs) have been used for the treatment for recurrent pregnancy loss (RPL) for a long time. We aimed to investigate the efficacy of the LMWHs on angiogenesis and apoptosis during placentation. A total of twenty-four rats were randomly divided into three groups each containing 8 rats: normal saline; enoxaparine sodium 0.4 ml, and enoxaparine sodium 0.8 ml were given to the Group 1, 2 and 3, respectively. Normal saline and enoxaparine sodium 0.4 ml or 0.8 ml were given to the rats beginning on the day the pregnancy was detected and continued until the 15th day of the pregnancy. The tissues containing placental decidual zone were immunostained for vascular endothelial growth factor A (VEGF-A) and caspase 7. The decidual and placental VEGF-A and the decidual caspase 7 immunostaining scores of all of the groups were high, however, there were no statistically significant differences among the groups (p>0.05). On the other hand, the placental caspase 7 immunostaining scores of the normal saline group were significantly lower than those of the enoxaparine sodium 0.4 and the enoxaparine sodium 0.8 groups (p<0.05). LMWHs seem to have effects on placental angiogenesis and apoptosis.