Effects of Cadmium on the Rat Salivary Glands, During Lactation

Cadmium (Cd) in air, drinking water and food has the potential to affect the health of people, mainly those who live in highly industrialized regions. Cd affects placental function, can cross the placental barrier and directly modify fetal development. Once the organism is particularly susceptible to the exposition to the Cd during the perinatal period, and that this metal can be excreted in the milk, the aim of the present work was to study the effects of the constant exposition to drinkable water containing low levels of Cd during the lactation, on the salivary glands of the rat. Female rats received ad libitum drinking water containing 300mg/l of CdCl2 throughout the whole lactation. Control animals received a similar volume of water without Cd. Lactant rats (21 day old) were killed by lethal dose of anesthetic. The salivary glands were separated, fixed in ""alfac"" solution for 24 h, and serially sectioned. The 6 mu m thick sections were stained with hematoxylin and eosin. Nuclear glandular parameters were estimated, as well as cytoplasm and cell volume, nucleus/cytoplasm ratio, number and surface density, diameters and cell thickness. Mean body weight was 34.86 g for the control group and 18.56 g for the Cd-treated group. Histologically, the glandular acini were significantly smaller, the gland ducts were similar in both groups studied. The connective tissue was more abundant. In conclusion, the salivary glands (submandibular, parotid and sublingual) showed retarded growth after Cd intoxication.

Trophoblast phagocytic program: roles in different placental systems

Although not belonging to the class of professional phagocytes, in many species trophoblast cells exhibit intense phagocytic activity. The complete range of physiological functions of trophoblast phagocytosis has not yet been fully characterized. Close association between the trophoblast and nutrition was determined many years ago. Hubrecht (1889) when proposing for the first time the name trophoblast to the external layer of the blastocyst, directly established the nutritive significance of this embryonic layer. Indeed, histotrophic phagocytosis, i.e. the internalization of maternal cells and secreted materials, is considered an important function of the trophoblast before the completion of the placenta. Recently, however, unexpected characteristics of the trophoblast have significantly enhanced our understanding of this process. Roles in acquisition of space for embryo development, in tissue remodeling during implantation and placentation and in defense mechanisms are highlighting how this cellular activity may be relevant for the maternal-fetal relationship beyond its nutritional function.