Spectroscopic investigations of sublethal doses of platinum group metals on chick embryo bone development

Abstract

<p>Platinum group metals (PGMs) are found at pollutant levels in the environment and are known to bioaccumulate in various plant and animal tissues. Our previous studies showed that chick embryos exposed to PGMs concentrations of 5.0 ppm (LDSO) and higher presented skeletal deformities. In this study, the effects of PGMs on the skeletal formation of developing chick embryo tibiotarsi were investigated at sublethal doses through the use of various spectroscopic methods. Chick embryos were injected with 1 mL of 1.0 ppm Pd(ll), Pt(lV), Rh(lIl) aqueous salt solutions and a PGM mixture on the 7th and 14th day of incubation. Control groups with no-injection and 1 mL injections of saline solutions were included. Embryos were sacrificed on the 20th day and tibiotarsi were harvested. MicroRaman imaging of the paraffin embedded cross-sections of tibiotarsi revealed anomalous calcium inclusions within the bone marrow for the PGM treatment. Hyperspectral Raman data were analyzed using in house-written codes within MatLab v. 7.11.0 R201Ob. Raman univariate chemical maps were created using the baseline-corrected intensity of the v1(P043-) stretching. Significant changes in the average mineralization age of tibiotarsi (integrated area ratio, v1(C032-)jv1(P043-)) were found in the Pt, Pd, and PGM treatments when compared to control (one-way ANOVA, p ≤0.001). Flame atomic absorption spectroscopy revealed ~50% change in the percent calcium content for the Pd and Pt treatments with respect to the no-injection control (17.05%). PGM concentrations in all tibiotarsi were below inductively-coupled-plasma optical-emissionspectroscopy detection levels. Overall, spectroscopic results show sublethal doses of PGMs negatively impact bone development.</p><p>This presentation occurred at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 8, 2011</p>