The Study Of The Toxic Effects Of Sodium Selenate/Selenite Anhydrous On Rana Nigromaculata Tadpoles

In this study, Rana nigromaculata tadpoles are used as subject, and the toxic effects ofdifferent concentrations of Na₂SeO₄ and Na₂SeO₃ on Rana nigromaculata tadpoles arestudied to reveal the toxic mechanism of these chemicals, to supplement methods andbiological symbols to detect environment pollution. The study also offers scientific evidenceto protect amphibians and pathologic reference to amphibians' cultivation.Analysis of environment background. The HG-ASF is adopted to measure the content ofselenium in environmental water and experimental water. Four kinds of cations are measuredusing High Performance Capillary Electrophoresis(HPCE), therefore the accuracy of thisexperiment is ensured.The cute toxicity experiment of Na₂SeO₄ and Na₂SeO₃ to Rana nigromaculata tadpoles.The 96h LC50 of Na₂SeO₄ and Na₂SeO₃ to 29³0 tadpole of Rana nigromaculata are94.8mg/L and 33.5mg/L. Our result shows that these two kinds of selenates both have stronglethal effect on Rana nigromaculata. In addition, there is a dose-effect relationship betweenthe chemicals and their toxicity effect.The injury of Na₂SeO₄ and Na₂SeO₃ to the liver tissues of Rana nigromaculata tadpolesparaffin section of livers and HE dyeing are performed. The injury contains liver cellsaggregation, blood antrum of liver increases and enlarges. The apparent features are theappearance of Kupffercells (KC) who have already licked up abnormal liver cells. Thenumber of activated KC increases with the enhancement of the concentrations of toxicselenates. The group using Na₂SeO₄ group takes on positive relationship and possesses welldose-effect relationship, while the group using Na₂SeO₃ reveals a tendency of first increasingand then declining.The injury of Na₂SeO₄ and Na₂SeO₃ to erythrocyte. The Na₂SeO₄ and Na₂SeO₃ lead tothe existence of micronucleus and the abnormality of the nuclear. In the Na₂SeO₄ group,nuclear pycnosis and nuclear fission occurs, and in the Na₂SeO₃ group, nuclear pycnosis andnuclear concavity are the main symptoms. The rate of micronucleus and the abnormality ofnuclears varies depending on the concentration of selenites and the wave crests of Na2SeO4and Na2SeO3 differ from each other. On the whole, every index reflects a tendency of firstincreasing and then declining.The genetic toxicity of Na2SeO4 and Na2SeO3. The Agarose Gel Electrophoresis(AGE) isused to detect the injury of DNA under the treatment of Na2SeO4 and Na2SeO3. The moreseverely the DNA is damaged, the more segments are produced and the smaller the segmentsare. As a result, the amount of migrating DNA is larger and the migrating distance is longer.The result shows that the Na2SeO4 and Na2SeO3 damage the genome DNA of Rananigromaculata tadpoles to different extent.Reversed Phase-High Performance Liquid Chromatographic (RP-HPLC),which is aimedat measuring the content of reduced GSH in the tissues of amphibians, is established. Usingthis method, the GSH content of Rana nigromaculata tadpoles under different concentrationsof Na2SeO4 and Na2SeO3 were measured. The induce of selenate to the content of GSH intadpoles makes its variation has well time-effect and dose-effect relationship. Thesephenomena demonstrate that GSH is smart to the exposure of selenate, and therefore can beused as a sensitive index to selenate pollution.