Haemopoietic and osteogenic toxicity testing in vitro using murine bone marrow cultures

Area of Science:

• Toxicology
• Hematology
• Biochemistry

Background:

• Bone marrow harbors stem cells essential for lifelong blood and bone cell production.
• Damage to these stem cells can lead to hematopoietic failure, blood disorders, or bone diseases.
• The accumulation of lipophilic and electrophilic substances in bone marrow highlights its vulnerability to circulating chemicals.

Purpose of the Study:

• To establish and validate a battery of in vitro bone marrow assays for screening chemical interference with hematopoietic, stromal, and bone-forming marrow cells.
• To assess the specificity of chemical effects on bone marrow cells by comparing them to general cytotoxicity in 3T3-fibroblasts.
• To evaluate the potential of these assays for screening both pollutants and cytokines for their effects on bone marrow.

Main Methods:

• Development of in vitro assays using bone marrow cells, including stromal cells cultured with ascorbic acid and beta-glycerophosphate to induce bone-specific matrix production and calcification.
• Inclusion of a general cytotoxicity assay using 3T3-fibroblasts to determine the specificity of observed effects.
• Exposure of assays to various concentrations of xenobiotics (e.g., lead nitrate, hydroquinone, catechol, benzene, phenol) and cytokines (e.g., interleukin 10) over 3 days.

Main Results:

• Lead nitrate demonstrated specific toxicity to stromal stem cell proliferation and calcification at lower concentrations than those affecting 3T3 fibroblasts.
• Hydroquinone, a benzene metabolite, showed equal inhibition across marrow assays but required higher concentrations to inhibit 3T3 cells, indicating some specificity.
• Catechol, another benzene metabolite, was highly toxic but equally effective across all assays, showing no specific bone marrow toxicity. Benzene and phenol exhibited minimal effects in vitro.
• Interleukin 10 demonstrated differential effects on bone marrow cells, highlighting the assays' utility for cytokine screening.

Conclusions:

• The developed in vitro bone marrow assays are effective in screening for specific toxicity of chemicals and cytokines.
• These assays can differentiate between general cytotoxicity and specific effects on hematopoietic, stromal, and bone-forming marrow cells.
• The findings support the use of these assays for early detection of potential bone and blood disorders caused by chemical exposure.