05.06.2013 Views

PNNL-13501 - Pacific Northwest National Laboratory

PNNL-13501 - Pacific Northwest National Laboratory

PNNL-13501 - Pacific Northwest National Laboratory

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

CFU-S Stem Cell Assay -<br />

Benzene Metabolites<br />

% of Control<br />

100<br />

10<br />

1<br />

Phenol<br />

HQ<br />

0 10 20<br />

Dose (uM)<br />

30 40<br />

phenol treatments were 51, 60, and about 1% of control,<br />

respectively. However, the chemical treatments of CFU-<br />

S cells in the presence of the radiation did not appear to<br />

shift the dose-response beyond what the chemicals<br />

accomplished by themselves. These preliminary in vitro<br />

studies suggest that the cytotoxic effects of benzene<br />

metabolites and radiation on bone marrow stem<br />

progenitor cells may be independent. Future studies are<br />

needed to determine if a similar response is seen<br />

following in vivo exposure to benzene and radiation.<br />

Summary and Conclusions<br />

An in vitro bone marrow stem cell culture assay for<br />

evaluation of chemical and radionuclide interactions was<br />

established. Preliminary experiments demonstrated that<br />

the colony-forming assay was sensitive to dose-dependent<br />

radiation effects. The benzene metabolites phenol and<br />

hydroquinone produced a dose-dependent inhibition of<br />

stem cell colony formation (CFU-S). The metabolite<br />

combination effect was multiplicative (greater than<br />

% of Control<br />

100%<br />

10%<br />

1%<br />

50.73%<br />

16.87%<br />

Treatment Groups<br />

40 FY 2000 <strong>Laboratory</strong> Directed Research and Development Annual Report<br />

1.13%<br />

HQ (10 uM)<br />

Phenol (40 uM)<br />

Phenol (40uM) +<br />

HQ (10uM)<br />

Figure 3. CFU-S cell colony formation response following in<br />

vitro exposure to phenol, hydroquinone, and phenol plus<br />

hydroquinone<br />

% of Control<br />

120<br />

100<br />

80<br />

60<br />

40<br />

20<br />

0<br />

CFU-S Stem Cell Assay - Radiation/Benzene<br />

Metabolites Co-Exposure<br />

100<br />

86<br />

60<br />

51<br />

45 43<br />

34<br />

13<br />

23<br />

15<br />

19<br />

12<br />

1.1 1.6 1.0 0.3<br />

0 0.01 0.1 1<br />

Radiation Dose (Gy)<br />

Radiation Only<br />

Radiation + 10 uM<br />

HQ<br />

Radiation + 40 uM<br />

Phenol<br />

Radiation + 40 uM<br />

Phenol/10 uM HQ<br />

Figure 4. CFU-S cell colony formation response following in<br />

vitro exposure to both radiation (0 to 1 Gy) and phenol,<br />

hydroquinone, and phenol plus hydroquinone. Percent of<br />

control values for each treatment are presented over the bar<br />

graphs.<br />

additive). Under in vitro exposure conditions, radiation<br />

did not shift the dose-response beyond what the benzene<br />

metabolites could accomplish independent of radiation.<br />

Future studies will determine if a similar response is<br />

obtained in mice following in vivo mixed chemical and<br />

radiation exposures. The approaches developed in this<br />

project will form the experimental cornerstone for<br />

pharmacodynamic model development for chemical and<br />

radiation interactions on bone marrow cells.<br />

References<br />

Corti M and CA Snyder. 1998. “Gender- and agespecific<br />

cytotoxic susceptibility to benzene metabolites in<br />

vitro.” Tox. Sci. 41:42-43.<br />

Cox, Jr. LA. 1996. “Reassessing benzene risks using<br />

internal doses and Monte-Carlo uncertainty analysis.”<br />

Environ. Health Perspect. 104 (Suppl. 6):1413-1429.<br />

Farris G M and SA Benjamin. 1993. “Inhibition of<br />

myelopoiesis by conditioned medium from cultured<br />

canine thymic cells exposed to estrogen.” Am. J. Vet Res.<br />

54:1366-1373.<br />

Farris GM, SN Robinson, KW Gaido, BA Wong, VA<br />

Wong, WP Hahn, and RS Shah. 1997. “Benzeneinduced<br />

hematotoxicity and bone marrow compensation<br />

in B6C3F1 mice.” Fundam. Appl. Toxicol. 36:119-129.<br />

Green JD, CA Snyder, J LoBue, BD Goldstein, and RE<br />

Albert. 1981. “Acute and chronic dose/response effects<br />

of inhaled benzene on multipotential hematopoietic stem<br />

(CFU-S) and granulocyte/macrophage progenitor (GM-<br />

CFU-C) cells in CD-1 mice.” Toxicol. Appl. Pharmacol.<br />

58:492-503.<br />

Scheding S, M Loeffler, S Schmitz, HJ Seidel, and HE<br />

Wichmann. 1992. “Hematotoxic effects of benzene<br />

analysed by mathematical modeling.” Toxicol. 72:265-<br />

279.<br />

Timchalk C, JE Morris, and RA Corley. 2000. “Effects<br />

of co-exposure of benzene and radiation (Yttrium-90) on<br />

hematopoiesis in CBA/CA mice.” Tox Sci. 54(1):1649.<br />

Publication<br />

Timchalk C, JE Morris, and RA Corley. 2000. “Effects<br />

of co-exposure of benzene and radiation (Yttrium-90) on<br />

hematopoiesis in CBA/CA mice.” Tox Sci. 54(1):1649.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!