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Objective To understand the effect of butylbenzyl phthalate(BBP) on the levels of DNA-protein crosslinks(DPC) in hepatic cells of mice.Methods Twenty-five male Kunming mice were randomly assigned into five groups(n=5).BBP was administered by intraperitoneal injection at doses of 0(control group),125,250,500,1 000 mg/kg respectively for 14 consecutive days.Then the levels of DNA-protein crosslinks were detected.Results DPC coefficient increased with concentration of BBP increasing.Treatments of 500 and 1 000 mg/kg BBP significantly increased the levels of DPC compared with the control group. Conclusion BBP can not cause DPC at low levels(125 mg/kg),but it can cause DPC significantly at high levels(500 and 1000 mg/kg),which may cause serious DNA damages.
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0.05).Conclusion The study suggests that the coefficient of DNA-protein crosslinks can be increased significantly by higher concentrations of FA in A549 cell lines.DPC induced by FA could be repaired.
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0.05),but as formaldehyde concentration increased,the coefficient of DPC also increased gradually.Higher concentration exposure(1.0,3.0 mg/m~3)resulted in significant elevation of DPC amount compared with the control group(P
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0.05), but DPC coefficient increases along with concentration of DEHP (125 mg/kg, 250 mg/kg, 375 mg/kg) rising, and it can cause DPC significantly (P
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0.05)and could be induced significantly after 12 h (P
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Genotoxic agents can induce various DNA lesions. DNA-Protein Crosslinks(DPCs) were known as the important DNA lesions which could impair gene expression because DPCs had a high probability of resisting repair and persisting through cell cycle. This repair resistance of DPCs could have biological significance but had not been evaluated clearly yet. Most of the studies that have evaluated the repair of DPCs only compared the extent of DPCs repair with other DNA lesions. We injected K2CrO4, a genotoxic agent, into Sprague-Dawley rats intraperitoneally(5mg/kg) and isolated blood lymphocytes 12 hours later. These lymphocytes were cultured in the mitogen added growth media and mitogen free media separately. The degree of the repair of DPCs was monitored for 4 days by the K-SDS assay. 4 day later, the amount of DPCs decreased by 4.6% in the mitogen added media but in creased by 10.9% in the mitogen free media. These results showed that DPCs induced by K2CrO4 were not repaired easily and the DPCs were biologically significant DNA lesions. We thought the decrease of DPCs in the mitogen added media was not due to the repair of DPCs, but from the increase of normal cell proliferation. Therefore, it is very important to consider the proliferation of normal cells when estimating the repair of DPCs.
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Animaux , Rats , Cycle cellulaire , Prolifération cellulaire , ADN , Expression des gènes , Lymphocytes , Rat Sprague-DawleyRésumé
Carcinogenic materials used in. occupational setting are thought to induce cancer by acting on DNA. BenzoCa)pyrene and the metabolites activated by the rat microsomal fraction were treated to the BALB/3T3 cells to see the formation of DNA-Protein Crosslinks (DPCs) and the repair. We measured the DPCs by the K-SDS assay according to Costa. The results are as follows: 1) The cytotoxicity results showed that viable cells were decreased by the increase of the dose of benzo[a]pyrene and microsomal activated metabolites and the metabolites treated cells showed more cytotoxicity. 2) The amounts of protein-crosslinked DNA in control cells are 690 ng/ml. The amounts were increased to 920 ng/ml in benzoCa)pyrene 0.1 microgram/ml treated cells, 720 ng/ml in benzo[a]pyrene 1 microgram/ml treated cells, 1,243 ng/ml in benzo[a]pyrene 10 microgram/ml, treated cells. The DPCs were measured higher in the metabolites treated cells than the benzo[a]pyrene treated cells 3) The DPCs were highest in the benzo[a]pyrene 10 microgram/ml + microsomal fraction treated cells among all treated cells. The DPCs were measured in those cells at 12 hour, 24 hour, 48 hour and 72 hour later to monitor the change of the amount of DPCs to see the repair of DPCs. The result showed that the amount of crosslinked DNA were decreased by the time. But considering the cell proliferation, the DPCs amount were not changed much and the repair did not seem to occur well.
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Animaux , Rats , Prolifération cellulaire , ADNRésumé
Objective To study the effect of formaldehyde exposure on DNA-protein crosslinks (DPC) in buccal mucosa cells in students who were taking anatomy course.Methods The modified SDS-KCl precipitation assay published by Zhitkovich and Costa in 1992 was applied to detect DNA-protein crosslinks in human cells.And this method has been used to explore DPC induced by different pollutants in numerous studies.37 medical students (20 males and 17 females) aged 19.24?1.09 (mean?standard deviation) and 40 students (20 males and 20 females) in natural science college aged 19.55?0.99 (mean?standard deviation) were studied.The frequency of exposure to formaldehyde was 6 h per week in exposed group.Results Concentrations of formaldehyde in anatomy laboratory ranged from 0.42 to 1.57 mg/m3.Exposure to formaldehyde resulted in an increase of DNA-protein crosslinks.The percentage (mean?standard deviation) of DNA-protein crosslinks in exposed and nonexposed students were 25.72%?6.48% and 22.88%?5.34% respectively(P0.05).Conclusion The result of the present study suggests that formaldehyde exposure in medical students increases the frequency of DNA-protein crosslinks in buccal mucosa cells and females may be more sensitive to formaldehyde exposure.