ABSTRACT
Uranium [U(Ⅵ)] in the blood is known to form stable complexes with apotransferrin (apo-Tf), which plays an important role in mediating the cytotoxicity induced by U(Ⅵ) transported to cells. The present study aimed to establish an new in vitro screening model of U(Ⅵ) decorporation agents through exploring the capability of chelating agents competing with U(Ⅵ) binding to apo-transferrin based on enzyme-linked immunosorbent assay (ELISA). The optimal concentrations of apo-Tf coated antigen, Tf antibody, secondary antibody and U(Ⅵ) treatment were achieved and the stability and reproducibility of this method were validated by methodology study. Using this model, the ability of four chelating agents to mobilize the U(Ⅵ) binding to apo-Tf was evaluated, and the rank of competitiveness was catechol-3,6-bis(methyleiminodiacetic acid） (CBMIDA) ≈ Tiron > apo-Tf > DTPA-CaNa3 ≈ DTPA-ZnNa3. The efficacy of these chelating agents in removal of U(Ⅵ) was tested by animal experiments. The results showed that immediate administration of CBMIDA or Tiron after injection of U(Ⅵ) in mice significantly promoted urinary U(Ⅵ) excretion and reduced U(Ⅵ) accumulation in kidneys and femurs, while DTPA-CaNa3 and DTPA-ZnNa3 have no obvious effects as compared to U(Ⅵ)-exposed mice alone, which was consistent with the results of competitive ELISA method. The animal experiments conform to the rules of the Animal Research Ethics Committee of School of Pharmacy of Fudan University. These results show that the new proposed method is rapid, simple and convenient with good reproducibility and has the potential to be used for in vitro screening of U(Ⅵ) decorporation agents.
ABSTRACT
The study was to explore effects of Tongluo Xingnao effervescent tablets on the blood rheology, iNOS, VEGF and LDH-5 in multi-infarct dementia(MID) model rats. Establish MID model rats were induced by microthrombosis, from which 50 successful model rats were randomly divided into five groups, such as the model control group, the dihydroergotoxine mesylate tablets(hydergine) group(0.7 mg•kg⁻¹), Tongluo Xingnao effervescent tablets high-dose, medium-dose and low-dose groups(7.56, 3.78, 1.89 g•kg⁻¹). Another ten rats in the sham group were randomly selected as the parallel control group. Each group was orally administered with drugs for 90 days. The learning and memory ability was evaluated with the Morris water maze test, while the whole blood viscosity and the erythrocyte aggregation index derived from abdominal aorta were measured in different shear rates. In addition, the levels of VEGF and iNOS in the serum were determined by ELISA kits. The expression of LDH-5 in hippocampus of rats was measured with immunohistochemistry and image quantitative analysis. The result showed that Tongluo Xingnao effervescent tablets notably decreased the escape latency of MID model rats, increased times of entering into the escape platform and prolonged retention time in medium ring, meanwhile the whole blood viscosity in MID model rats was also notably reduced in four shear rates, i.e. 1, 5, 30, 200 S⁻¹, erythrocyte aggregation index, serum VEGF and iNOS, and average optical density value of LDH-5, with a statistically significant differences compared with the model control group (P<0.05). In conclusion, Tongluo Xingnao effervescent tablets could improve the ability of learning and memory of MID model rats and the blood rheology, reduce the level of iNOS, VEGF and the expression of LDH-5, and then improved the brain energy supply.