Objective To test the effects of taurine on striatum neurotransmitters in manganese exposed rats.
Methods A total of 156 healthy male SD rats were randomly divided into 1 control group, 3 manganese exposure groups (10, 15, and 20 mg/kg MnCl2, respectively), and 9 taurine intervention groups based on orthogonal design (100, 150, and 200 mg/kg taurine, respectively), with 12 rats in each group. The control group was intraperitoneally injected with equal amount of saline; the manganese exposure groups were intraperitoneally injected with MnCl2, once a day for continuously 12 weeks; the taurine intervention groups were treated with MnCl2 at the same dose as the manganese exposure groups, and intraperitoneally injected with taurine after MnCl2 injection on every Tuesday, Thursday, and Saturday for 12 weeks. All rats were sacrificed and striatums were removed to determine the levels of taurine, dopamine (DA), and 5-hydroxytryptamine (5-HT) by high performance liquid chromatography, the level of manganese by graphite furnace atomic absorption spectrometry, and monoamine oxidase (MAO) activity by UV spectrophotometry.
Results The average striatum manganese levels of the 3 manganese exposure groups(2.61±0.73), (2.75±0.37), and (2.98±0.52) μg/g, respectively and the 9 taurine intervention groups(2.52±0.74), (2.42±0.70), (2.57±0.40), (2.56±0.46), (2.51±0.51), (2.66±0.75), (2.82±0.98), (2.88±0.56), and (2.86±0.91) μg/g, respectively were higher than that of the control group(0.60±0.20) μg/g (Ps < 0.05). The average taurine level in the group exposed to 20 mg/kg manganese(712.68±128.69) μg/g was lower than that of the control group (P < 0.05). The average DA and 5-HT levels of the 3 manganese exposure groupsDA:(6 284.63±1 243.94), (6 173.54±826.68), and (6 014.21±636.48) μg/g, respectively; 5-HT:(172.22±23.79), (166.39±42.73), and (164.82±43.43)μg/g, respectively were lower than those of the control group(7 814.91±1 284.63)μg/g and (251.34±51.26)μg/g, respectively (Ps < 0.05). The taurine intervention at 150 and 200 mg/kg increased the levels of DA and 5-HT in the group exposed to 10mg/kg manganese (P < 0.05). The striatum monoamine oxidase activities of the 3 manganese exposure groups(14.65±1.89), (16.45±1.13), and (17.05±1.86) U/(h·mg), respectively were higher than that of the control group(12.64±1.10) U/(h·mg) (Ps < 0.05). The striatum monoamine oxidase activities of all the taurine intervention groups (except the group exposed to 10 mg/kg manganese and intervened with 100 mg/kg taurine) were significantly lower than those of the groups exposed to same dose of manganese (Ps < 0.05).
Conclusion Manganese could reduce the levels of taurine, DA, and 5-HT, and increase the enzyme activity of MAO in rat striatum. Taurine has a protective effect on the decrease of neurotransmitters in striatum of rats induced by manganese.
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