Objective To investigate the distribution characteristics of manganese in rats' tissues with 12-week manganese poisoning, and to observe the potential striatal lesion after high manganese accumulation.
Methods Twenty adult male SD rats were divided into one control group (n=10) and one manganese group (n=10), which were administered with saline and 15 mg/kg body weight manganese intraperitoneal injection respectively, once a day and 5 days a week for 12 weeks. Then, pathological changes of corpus striatums were observed by transmission electron microscope (n=2 for each group) and manganese contents in rats' tissues were detected by inductively coupled plasma mass spectrometry (n=8 for each group).
Results Compared with the control group, the rats exposed to manganese showed a slow increase of body weight. After 12 weeks of designed treatment, except lung and cerebellum, the manganese contents in the samples of liver, stomach, small intestine, colon, rectum, spleen, kidney, brain, testis, heart, hair were higher than those of the controls (P<0.05). The manganese content in the brain of the manganese group was higher(1.29±0.05)μg/g tissue than that of the control group(0.65±0.13)μg/g tissue (P=0.001). Meanwhile, a large amount of lipofuscin was accumulated in striatal neurons observed under transmission electron microscope.
Conclusion Manganese could accumulate in multiple tissues of rats after chronic manganese poisoning and affect digestive system, kidney, testis, and brain. Oxidative damage may be involved in the observed neurotoxicity.
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