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Effect of diquat on cell growth and macromolecule synthesis in cultured pneumocytes
Abstract:
The effects of diquat (DQ) on cell growth and macromolecule synthesis were investigated in cultured rat, feline and human. pneumocytes. DQ at 10(-3) M and 10 (-5) M showed time- and dose-dependent inhibition of cell growth for 7 days. The incorporation of 3H-thymidine, 3H-uridine and 14C-leucine into DNA, RNA and protein was reduced to 0-47% by 10(-3) M of DQ, and that of 14C-leucine into protein of A-549 cells was reduced to 67% by 10(-5) M of DQ. Among the cells examined, A-549 cells derived from human lung were the most resistant to the inhibitory effects of DQ on cell growth and macromolecule synthesis. On the other hand, human lung embryonic fibroblast cells and L-2 cells derived from rat lung were the most sensitive to the toxicity of DQ. These results indicate that the inhibitory effects of DQ on cell growth and on macromolecule synthesis are dependent on the concentrations of DQ administrated, and that species differences in the sensitivity to DQ toxicity may exist.
Insights
Diquat (DQ) inhibits lung cell growth and macromolecule synthesis in a dose-dependent manner. Species differences in sensitivity to diquat toxicity were observed, with human lung cells showing more resistance.
Area of Science:
- Toxicology
- Cell Biology
- Environmental Health
Background:
- Diquat (DQ) is a widely used herbicide with known toxicity.
- Understanding its effects on lung cells is crucial for assessing health risks.
Purpose of the Study:
- To investigate the impact of diquat on the growth and macromolecule synthesis of cultured lung cells from different species.
- To determine the dose- and time-dependency of diquat's inhibitory effects.
- To identify potential species-specific differences in sensitivity to diquat toxicity.
Main Methods:
- Cultured rat, feline, and human pneumocytes were exposed to varying concentrations of di diquat (10(-3) M and 10(-5) M) for 7 days.
- Cell growth was monitored over the exposure period.
- Incorporation of radiolabeled precursors (3H-thymidine, 3H-uridine, 14C-leucine) into DNA, RNA, and protein was measured to assess macromolecule synthesis.
Main Results:
- Diquat exhibited time- and dose-dependent inhibition of cell growth across all tested cell types.
- Macromolecule synthesis (DNA, RNA, protein) was significantly reduced by diquat exposure, with 10(-3) M DQ reducing incorporation by 0-47%.
- A-549 human lung cells demonstrated the highest resistance to diquat's inhibitory effects, while human lung embryonic fibroblast and rat L-2 cells were most sensitive.
Conclusions:
- Diquat's inhibitory effects on lung cell growth and macromolecule synthesis are concentration-dependent.
- Significant species differences exist in the sensitivity of lung cells to diquat toxicity.
- These findings highlight the need for further investigation into the mechanisms underlying diquat-induced lung toxicity and species-specific responses.