Haemodynamic effect of nickel chloride in pregnant rats

Non-pregnant and pregnant CFY rats were given 3 mg/kg nickel chloride or physiological saline by gavage daily for eight days during days 7-14 of organogenesis. The haemodynamic investigations were carried out using 113Sn labelled microspheres. Nickel concentrations in maternal and fetal blood, as well as in amniotic fluid were determined by atomic absorption spectrophotometry. It was found, that nickel crossed the placenta, appeared in the fetal blood and amniotic fluid, where its concentration depended on the dose given to the pregnant animal and the nickel concentration of the maternal blood. Nickel chloride influenced neither the systemic haemodynamic parameters (arterial blood pressure, total peripheral resistance--TPR, cardiac index) nor the values of the organ (including the placenta) circulation indices, neither in the pregnant nor in the non-pregnant animals. It is concluded that in the pathomechanism of embryotoxicity (causing weight gain retardation) and teratogenicity (causing major anomalies of the uropoietic apparatus) of nickel, demonstrated earlier, the assumed effects of nickel on maternal and placental circulation probably do not play role (as such effects could not be detected). The direct embryo-damaging effect of nickel crossing the placenta (direct cytotoxic effect) may be held responsible for the embryotoxicity and teratogenicity of nickel.