| Objectives Rats model of lead exposure was established to screen the key copper related proteins in rat hippocampus.Meanwhile,the role of CD200 and CD200 R proteins in hippocampus inflammation induced by lead exposure of rats was explored.Our finding provide theoretical basis for of lead neurotoxicity mechanism and prevention.Methods A total of 45 SPF SD male healthy rats were randomly divided into control group,low lead exposure group and high lead exposure group,with 15 rats in each group.The rats in low lead exposure and high lead exposure group were given 0.25 g/L or 0.5 g/L lead acetate respectively,and rats in the control group were given the same amount of double distilled water and exposure of 20 week.Morris water maze experiment was used to test the spatial learning and memory ability of experimental rats.HE staining was applied to observe the histopathological changes of rat hippocampus.ICP-MS was used to determine the contents of lead and copper in hippocampus of rats.Cu-IMAC technology was applied to isolate the copper related proteins in rat hippocampus.After that,the copper binding protein was identified and analyzed by iTRAQ combined with LC-ESI-MS/MS technology.Western blot was used to detect the expression of copper protein CD200 and its receptor CD200 R in rat hippocampus.The protein location of CD200 and CD200 R protein was observed by laser scanning confocal microscope.Western blot was used to detect the changes of protein expressions of Iba1,IL-1?,TNF-?,IL-6,and IFN-? in hippocampus of rats.Results 1 Morris water maze test results showed that the escape latency of rats exposed to low lead and high lead increased than that of control group,and the times of crossing platform decreased significantly.2 HE pathological detection showed that hippocampus neuron arrangement was disorder,with reduction of cell number and deep staining of nucleus.3 Compared with the control group,the contents of lead and copper in the hippocampus of rats in low lead exposure group and the high lead exposure group were increased to(0.40±0.05)?g/g,(1.31±0.17)?g/g and(2.04±0.42)?g/g,(2.50±0.48)?g/g.4 Proteomic results showed that 3,641 copper binding proteins were isolated from rat hippocampus,of which,108 proteins of rat exposure group was identified with 65 upregulated proteins and 43 down-regulated proteins.And the change of CD200 in lead exposure group was 0.53 folds of the control group.5 The protein expression of CD200 in hippocampus of rats exposed to low and high lead was 69% and 59% of that of the control group respectively,while that of CD200 R in high lead exposed group was 53% of that of the control group(P<0.05).Compared with the low lead exposure group,the protein expression of CD200 and CD200 R in the high lead exposure group also decreased significantly.6 Compared with the control group,the fluorescence intensity of CD200 and CD200 R in high lead exposure group and low lead exposure group decreased.6 Compared with the control group,the expression of Iba1 protein in hippocampus of rats exposed to high lead increased 3.33 folds.There was no statistical difference between low lead exposure group and control group(P>0.05).The contents of IL-6,IL-1?,and TNF-? in hippocampus of rats exposed to low lead and high lead increased by 21% and 35%,78% and 112%,16% and 58% respectively than those of control group.The content of TNF-? in high lead exposure group increased respectively compared with low lead exposure group.The protein content of IFN-? in hippocampus of rats exposed to low lead and high lead decreased by 21% and 42%,respectively than that of control group.The protein content of rats exposed to high lead was lower than that of rats exposed to low lead,and the difference was significant.Conclusions Lead exposure can cause copper to accumulate in the hippocampus of rats,resulted in changes in the expression profile of copper related proteins in hippocampus of rats,and aggravating inflammatory damage.The copper related protein of CD200 and its receptor CD200 R may play a role in lead-induced neuroinflammation.Figure 11;Table 6;Reference 146... |
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