| Following the prohibition use of polybrominated diphenyl ether (PBDEs) in Europe and North America, hexabromocyclododecane (HBCD) become the largest user of brominated flame retardants, which is widely used in building thermal insulation materials, textiles, plastics, and circuit board. Although there are some correlated regulations in both of HBCD and PBDEs, but there are detected in such as air, water, soil, sediment, biological and human, and the detection volume is increasing year by year. They have already become the ubiquitous environmental pollutant. Research shows that, HBCD and PBDEs have similar sources, metabolic pathway and toxicity. They can interfere of normal development with human and animal’s brain, cerebellum and hippocampus, leading to neurological disorders, learning, memory function and happen to bioaccumulation easy. The development children are the high-risk population exposure to HBCD and PBDEs. The environmental release and respective toxicity are attracted inore attention, the combined pollution system that can produce potential hazards need to be studied.At present, there is less study about HBCD oxidative damage effect, and it is also limited about the composite exposure to HBCD and PBDEs.This paper is concerned about the development children are the high-risk population exposure to HBCD and PBDEs, according to glutathione antioxidant system, peroxides and reactive oxygen species (ROS) as research content, so as to revealed HBCD exposure and HBCD/DE-71compound exposure may produce oxidative damage effect. Select the Sprague-Dawley3-days new-born rats, they were let to be exposed to different doses of HBCD (10,50,100,300μg/kg body weight); and DE-71with the same concentration of HBCD ((10,50,100,300μg/kg body weight) and the volume ratio is HBCD:DE-71=2:1, mixing composite exposed concentration of10,50,100,300μg/kg-bw. Design21days,42days,90days for exposure time. The experimental results show that:In the rat liver, GPx activity were increased significantly in21d10～50μg/kg,42d10～100μg/kg and90d10μg/kg group (p<0.05); When exposed to HBCD/DE-71, it was increased significantly in21d300μg/kg and90d10～300μg/kg groups (p<0.05). When exposed to HBCD of21d and90d, all groups GR activity were lower than control group, and there were decreased significantly in21d50μg/kg,90d50μg/kg and300μg/kg group (p<0.05); When exposed of42d, all groups GR activity were higher than control group.50～300μg/kg groups were increased significantly (p<0.05); When exposed to HBCD/DE-71, the GR activity showed the opposite trend with HBCD exposure. In21d and90d,all groups GR activity were higher than controls,21d50～100μg/kg had a significant increasing trend (p<0.05). Exposed to42d, all groups GR activity were lower than control group, and each group had a significant change(p<0.05).When exposed to HBCD, all groups GCL activity were significantly decreased in21d and90d (p<0.05). it was also decreased significantly in42d10～50μg/kg groups (p<0.05); When exposed to HBCD/DE-71, all groups GCL activity were higher than control group in21d and42d, and there were increased significantly in21d10～100μg/kg,42d100μg/kg group (p<0.05).The activity of GCL in each group was significantly decreased in90d exposure (p<0.05).When exposed to HBCD, all groups of GSH content were increased than control group in21d and42d, there were increased significant in21d100μg/kg,42d10～300μg/kg group (p<0.05). When exposed to90d, it showed a decreased trend, and in50μg/kg,300μg/kg group decreased significant (p<0.05); The time of exposed to HBCD/DE-71, the GSH content had a significant increased In21d100μg/kg (p<0.05), had a decreased significantly in42d and90d300μg/kg (p<0.05).When exposed to HBCD, the content of GSSG were increased significantly in21d50～300μg/kg groups (p<0.05), but it was no significant change in42d and90d (p>0.05); When exposed to HBCD/DE-71, the GSSG content were decreased significantly in21d300μg/kg,42d100～300μg/kg and90d10μg/kg (p<0.05).By exposed to HBCD, the level of ROS in all groups had no significant changes in21d (p>0.05). There were significantly increased in42d50.300μg/kg and90d50～300μg/kg groups (p<0.05); By exposed to HBCD/DE-71, ROS level was decreased significantly in21d50μ/kg group (p<0.05). Each group of ROS level had no significant in42d (p>0.05), but each group of ROS levels was higher than control group in90d, and10～50μg/kg,300μg/kg increased significantly (p<0.05).After HBCD exposure to21d and90d, LDH activity was increased significantly in21d50～300μg/kg,90d100μg/kg (p<0.05).The activity of LDH had no significant change in42d exposure (p>0.05); After HBCD/DE-71exposure, LDH activity was decreased significantly in21d300μg/kg group (p<0.05).Each group of the LDH activity had no significant change in42d exposure (p>0.05). When exposed to90d, the activity of LDH increased significantly10～50μg/kg group (p<0.05), decreased significantly in100～300μg/kg group (p<0.05). After HBCD exposure to21d and42d, the MDA content had no significant in each group (p>0.05); it was decreased significantly in90d100μg/kg group (p<0.05); After HBCD/DE-71exposure to21d and42d, the MDA content increased significantly in21d50～300μg/kg group,42d100～300μg/kg group (p<0.05); When exposed to90d, MDA content was decreased significantly in300μg/kg group (p<0.05).According to the experimental results, we could obtain the following conclusions:1.When exposed to HBCD of21d and42d, the GPx activity and GSH content showed a rising trend in10～100μg/kg group. It was showing that GPx, GSH were induced and produced defense responses when the contamination stress to organism; When the dose of300μg/kg, GPx, GSH happened to decrease, it was showed that a large amount of ROS increased beyond their defenses; Each group of GR, GCL activity was decreased in21d, it might be the primary oxidative stress have a certain inhibition effect; then they were increased in42d, it might be the antioxidant defense after organism under oxidative stress. The MDA concentrations which was a measure of the peroxidative damage remained relatively stable showed that different dose of HBCD exposed to21d and42d had no significant peroxidation effects, but Gpx, GSH and other indicators showed significant changes (p<0.05) and LDH activity increased significantly (p<0.05) indicate that pollutant exposure would produce bigger effect on organisms of the crucial period in the brain development.When exposed to90d, the level of ROS increased significantly (p<0.05); each group of GSH, GR, GCL was decreased; GPx activity appeared downtrend in50μg/kg group. Above these showed that a large number of ROS beyond the antioxidant defense ability of the long-term exposure, but the LDH and MDA were stay relatively stable may be long-term exposure can resist the pollution.2.When exposed to HBCD/DE-71, GPx, GSSG increased significantly in21d300μg/kg group (p<0.05); GSH decreased significantly in42d300μg/kg group (p<0.05); MDA content increased significantly in21d,42d (p<0.05); each group of GR, GCL activity changes in21d and42d, as well as ROS level changes in42d. Above these changes were differences with HBCD single exposure, it probably due to the antagonistic action of HBCD and DE-71. From the MDA content increased significantly we can see that the composite exposure exacerbates the peroxidation damage.When exposed to90d, LDH activity decreased at a higher exposure dose. The content of MDA was relatively stable, this was consistent with the HBCD single exposure, but the level of ROS increased significantly after a long-term exposure, this indicated that pollutant exposure may have a risk harm to the body. |
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