Objective To study the relationship among the concentrations of manganese, zinc, and zinc transporter 3 (ZnT3) in manganism rat hippocampus.
Methods Forty male SD rats were randomly divided into four groups with 10 rats in each group:high-dose group, middledose group, low-dose group, and control group. The four groups were given intraperitoneal injection of 3, 6, and 12 mg/(kg· d) MnCl2 solutions and normal saline (NS), respectively, for eight weeks. Animals in each group were sacrificed and hippocampus tissue samples were removed for determination. We observed the pathologic changes of hippocampi of the four groups by HE staining under microscope, detected Mn2+ and Zn2+ in hippocampus tissue by graphite furnace atomic absorption spectrometry, determined the concentration of ZnT3 protein by Western blot, and examined the expression of ZnT3 mRNA by real-time fluorescent quantitative PCR in rat hippocampus.
Results All groups exposed to manganese were observed changes in rat hippocampal neurons with eosinophilic degeneration, condensed cytoplasm, unclear cell composition, cell shrinkage, and eosinophilic body. Compared with the control group and the lowdose group, the concentrations of manganese and zinc were significantly higher in the high-dose group and the middle-dose group (P < 0.05), and the concentration in the high-dose group was higher than that in the middle-dose group (P < 0.01). The expression le vels of ZnT3 protein were 1.01±0.03, 0.80±0.02, 0.65±0.13, respectively, in the high-dose, middle-dose, and low-dose groups, higher than that of the control group (0.51±0.06) (P < 0.05). The expression levels of ZnT3 mRNA were 3.40±0.36 and 2.88±0.69, respectively, in the high-dose and middle-dose groups, higher than those in the control group and the low-dose group (1.47±0.60) (P < 0.001).
Conclusion Manganese can damage the structure of rat hippocampus neurons, and the concentration of zinc in hippocampus is elevated with the increase of ZnT3 in hippocampus.
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