CHROMIUM DISTRIBUTION AND TOXICITY IN MAMMALIAN CELLS

我们将通过做来检验铬的分布和遗传毒性

We will examine chromium distribution and genotoxicity by doing a systematic morphometric analysis of in vivo chromium toxicity in the liver, lung, kidney of mice injected with chromium. To date, in vivo studies have looked mainly for tumor induction at the sites of administration and have characterized chromium- induced malignancies at the level of the whole organ. Our research approach to the study of in vivo Cr effects will be the use of an innovative CAM (Computer-Assisted Microscopy) system to quantify changes in individual cells, as analyzed by cytochemical, histological, and radioautographic assays. Our in vitro findings led us to hypothesize that the chromium-sensitive cells are on the order of One Cell Among Many (OCAM), and that the ability to quantify individual cells was critical. With the computer's precision, speed, and memory, we can experimentally define and quantify Cr effects on individual cells (particularly, nuclei). Chromium genotoxicity, in vivo, will be studied systematically using the following research approaches: 1) To study acute and chronic toxic effects on the liver, lung, and kidney (with liver being the prototype organ) after chromium administration, using CAM-enhanced morphometric analysis. Acute toxicity studies will provide the basis for chronic studies. 2) To measure Cr distribution in tissues, using radioautographic and histochemical techniques augmented by the CAM system, to quantify Cr- binding in the nucleus and cytoplasm of individual cells. 3) To develop and verify other CAM-enhanced techniques to characterize nuclear or genomic changes in single cells: a) in situ hybridization, using mouse cDNA probes; b) textural analysis of nuclei obtained from different cellular states to characterize cell death (apoptosis and necrosis); c) electrophoresis/high performance liquid chromatography of chromatin components to characterize cell death. 4) The ultimate goal of our research is to correlate the findings of the chromium organ toxicity and distribution studies. With the CAM-stored database on chromium-induced changes, we will generate cell archetypes of liver, kidney and lungs, which have been sorted by treatment interval and dosage.