Cancer during pregnancy alters the activity of rat placenta and enhances the expression of cleaved PARP, cytochrome-c and caspase 3

Adult female Wistar rats (90 days old, n = 54) were allocated to control (C), tumour-bearing (W), or ascitic fluid-injected (A) groups and were killed on the 16th, 19th or 21st day of pregnancy. Placental tissues were analysed using biochemical and histochemical assays.The placental protein content and glutathione-S-transferase activity were decreased in groups W and A. Histochemical analysis showed an increase in the number of cells with cleaved PARP, caspase 3 and cytochrome-c in groups W and A, indicating that the tumour growth clearly damaged placental tissue and affected the levels of apoptotic factors. These results were confirmed by western blotting.Since trophoblastic cells are responsible for maintaining a normal placental function, the uncontrolled death of these cells in response to tumour cell growth or substances derived from ascitic fluid could have a negative impact on foetal development. Further knowledge of these events may help to preserve the foetus and placenta during development.Cancer is the second most common cause of death during the reproductive years [1] and complicates 0.02–0.1% of all pregnancies [2]. However, the development of cancer during pregnancy is difficult to predict [3]. Indeed, some studies have suggested that pregnancy does not favour the development of cancer and may protect the organism against tumour growth [3,4]. Fast tumour growth during pregnancy may result in damage to the foetus and lead to foetal resorption and death [4-6]. Since foetal and tumour growth requires increased protein synthesis, the importance of amino acids in foetal life has been emphasised [7].The foetal nutrient supply depends on the mother's reserves and food intake, as well as on the placental function. Placental growth increases during gestation, concomitant with or ahead of foetal growth [8], and a failure in placental function can adversely affect foetal growth or welfare [7]. The physiological changes that occur during pregnancy can only be sust