Abstract: ObjectiveTo explore the antagonism of manganese to toxicity of cadmium(Cd) in pregnant rats.MethodsPregnant Wistar rats were divided into three groups:Cd-poisoning group,manganese supplement group and control group.All pregnant rats were weighed on the 7th,9th,11th day,and those in the first two groups were given injection with cadmium chloride for intoxication.On the 20th day during gestational period all rats were anaesthetized to draw blood for a test,killed to observe growth condition of fetuses.Rats' liver and kidney were extracted to make tissue sections for optical and electron microscopic examination.The contents of cadmium and manganese in blood,liver and kidney were determined.ResultsThe growth rate of rats,the proportion of living fetuses and their average weight in the manganese supplement group increased significantly compared with those of Cd-intoxication group,while the incidence of malformed fetuses and absorbed embryos decreased greatly (P<0.01).The structures of liver and kidney cells of rats in manganese supplement group were close to normal.The content of cadmium in blood,liver and kidney of manganese supplement group was lower than that of the Cd-poisoning group significantty(P<0.01),but the content of manganese has not changed obviously.ConclusionThe adequate manganese supplement can antagonize the development disorder and cell damage in liver and kidney of rats induced by cadmium.