Effects of polygala on the neurogenesis of manganese poisoned mice / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of polygala on leaning and memory and the expression of Microtubule associated protein on manganese poisoned mice.</p><p><b>METHODS</b>60 female Kunming mice were randomly and equally divided into 5 group. They are normal control group (CG), manganese poisoned group (MG), manganese poisoned with polygala high dose group (MHG), manganese poisoned with polygala middle dose group (MMG), manganese poisoned with polygala low dose group (MLG). The model of manganese poisoned mice was prepared of the way of intraperitoneal injection of manganese chloride (MnCl2 15 mg/kg), the spatial learning and memory ability was tested by Morris water maze, the Doublecortin (DCX) was tested by the way of immunofluorescent staining in the SVZ and SGZ.</p><p><b>RESULT</b>In the navigation test, compared with MG, the escape latency of MHG, MMG and MLG were significantly decreased (P < 0.05), in space exploration experiments, MHG, MMG, MLG compared with MG, the number increased significantly across platforms (P < 0.05). compared with MG, the DCX expression of MHG, MMG and MLG were significantly increased (P < 0.05).</p><p><b>CONCLUTION</b>The leaning and memory ability of manganese poisoned mice can be improved by the polygala, and the mechanism may be related to promote the expression of DCX and neurogenesis in the brain.</p>

Manganese neurotoxic effect and its susceptibility biomarkers of choice / 中华预防医学杂志

Long-term occupational exposure to manganese might cause manganese poisoning, which would had adverse effects on nervous system of workers. The basal nucleus was damaged and dopaminergic neuron was injuried by manganese. The mechanism could be related with interfering the energy metabolism of central nerve, changing neurotransmitters, activating oxidation system and so on. Genetic factors may also plays a significant role in the neurotoxicity caused by manganese. Study the effects of manganese exposure biomarker, the neurotoxicity of biomarkers and the genetic susceptibility to early and susceptibility biomarkers will contribute to the prevention and control of manganese neurotoxicity.

Effects of enriched environment and impoverished environment on learning and memory ability of manganese-exposed mice / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of enriched environment and impoverished environment on the learning and memory ability of manganese-exposed mice and the mechanism.</p><p><b>METHODS</b>Forty female Kunming mice were randomly and equally divided into 4 group: control group (CG), standard environment and manganese exposure group (SEG), enriched environment and manganese exposure group (EEG), and impoverished environment and manganese exposure group (IEG). The mouse model of manganese poisoning was established by intraperitoneal injection of manganese chloride. The learning and memory ability was tested by Morris water maze. The expression of cAMP response element-binding protein (CREB) in area CA1 of the hippocampus was measured by immunohistochemistry.</p><p><b>RESULTS</b>In place navigation test, the SEG had a significantly longer escape latency than the CG (P < 0.05), and the EEG had a significantly shorter escape latency than the SEG (P < 0.05); there was no significant difference in escape latency between IEG and SEG (P > 0.05). In spatial probe test, the EEG had a significantly greater number of platform crossings than the SEG (P < 0.05), and the IEG had a significantly smaller number of platform crossings than the SEG (P < 0.05). The expression of CREB in area CA1 of the hippocampus was significantly lower in IEG and SEG than in CG (P < 0.05), and it was significantly higher in EEG than in SEG (P < 0.05).</p><p><b>CONCLUSION</b>In the enriched environment, the learning and memory ability of manganese-exposed mice can be improved, which may be due to the increased expression of CREB in the hippocampus.</p>

Effect of manganese chloride on the ovarian development in female mice

Manganese [Mn] is a naturally occurring essential trace element that present as a solid substance with a water soluble property. In the body Mn is absorbed in the intestine and present with a higher concentration in many tissues; It was reported that manganese, is one of the most used metals in the industry, Recently, several new manganese compounds have been used for fungicides and petrol production, in addition to its use as contrasting agent in magnetic resonance tomography. The manganese chloride solution [8000mg/liter] was orally administered via gastric tubes in a dose of 0.1mL/day to 30 pregnant female mice and this considered as treated group, while the control group was given distilled water only in a same dose and route of administration. The number of the born litters was recorded for both groups. Then from the female offspring; blood was aspirated FSH and LH level was evaluated and the ovaries were excised and processed for histological observations. The recorded results showed significant decrease in the number of the litters of both sexes in the treated group compared to control one. The histological features of the mice ovaries which were born by the treated group exhibited structural changes in comparison to control group. The FSH and LH hormones level also showed significant changes in treated group compared to control group. The recorded results of this study assess the presence of teratogenic effect of manganese chloride on the developing ovaries and the hormonal level of the mice exposed to MncL[2] in utero

Relationship between mRNA expression of MnSOD and manganese neurotoxicity / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the relationship between mRNA expression of manganese superoxide dismutase (MnSOD) and manganese neurotoxicity.</p><p><b>METHODS</b>Thirty-one patients with occupational chronic manganese poisoning (case group), as well as 31 controls exposed to the same condition (control group), were included in the study. Whole blood RNA was extracted, and the mRNA expression of MnSOD was measured by RT-PCR; the two groups were compared in terms of the mRNA expression of MnSOD. PC12 cells were treated with 0, 100, 200, 400, 600, 800, and 1000 ümol/L MnCl₂ for l, 2, 3, and 4 d; the cell viability was determined by MTT assay, and the mRNA expression of MnSOD was measured by RT-PCR.</p><p><b>RESULTS</b>The case group had significantly lower mRNA expression of MnSOD than the control group (0.390 ± 0.080 vs 0.582 ± 0.219, P < 0.05). MnCl2 had a toxic effect on PC12 cells; the concentration of MnCl₂ was positively correlated with the toxic effect but negatively correlated with the mRNA expression of MnSOD.</p><p><b>CONCLUSION</b>MnSOD mRNA may be involved in the manganese-induced damage of nerve cells. It is hypothesized that high mRNA expression of MnSOD may play an inhibitory effect on manganese neurotoxicity.</p>

Relationship between MnSOD polymorphisms and susceptibility of chronic poisoning exposed to manganism occupationally / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the relationship between polymorphisms of MnSOD and the susceptibility of chronic poisoning exposed to manganism occupationally.</p><p><b>METHODS</b>In a study of case-control, genotypes were determined by PCR-RFLP in 164 patients with chronic occupational mangamism poisoning and 328 controls with age- and sex-matched for MnSOD 9Ala-Val.</p><p><b>RESULTS</b>There was a significant difference in the frequency of MnSOD 9Ala-Val at V locus mutant allele between cases and controls (χ(2) = 15.225, P < 0.01, 95%CI = 1.43 ∼ 3.00). Individuals with the genotype VV had a 1.30 of risk increase of occupational chronic manganism poisoning compared with the the genotype AV or AA (OR = 2.30, 95%CI = 1.52 ∼ 3.49, P < 0.05).</p><p><b>CONCLUSION</b>The MnSOD polymorphisms may be related with the susceptibility to chronic occupational manganism poisoning, the risk of chronic occupational manganism poisoning increases in carriers with genotype VV at MnSOD 9Ala-Val locus.</p>

Early biological markers of manganese exposure / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the biomarker of manganese exposure by analyzing the relationship between manganese exposure and concentration in some biomaterials.</p><p><b>METHODS</b>The air samples were collected through the individual air sample. According to the manganese levels in the air, workers were assigned to control group, low concentration group and high concentration group, and manganese in the hair, urine, serum, blood cell and saliva from different group were measured respectively. The correlations between concentration of external manganese exposure and manganese concentrations in biomaterials, and years of employment and concentrations in biomaterials were analyzed.</p><p><b>RESULTS</b>In the high concentration group, saliva manganese was 32.17 µg/L, hair manganese was 37.39 mg/kg, urine manganese was 2.50 µg/L, plasma manganese was 29.61 µg/L, blood manganese was 14.49 µg/L, were higher than those in the control group (10.40 µg/L, 1.60 mg/kg, 0.77 µg/L, 10.30 µg/L, 4.56 µg/L respectively) (P < 0.01). The manganese concentration in the saliva was significantly correlated with airborne manganese concentration (r = 0.649, P < 0.01), with the years of employment (r = 0.404, P < 0.01), with the total exposure of manganese (r = 0.342, P < 0.01), with the manganese concentration of plasma (r = 0.303, P < 0.01) and with the manganese concentration in blood cells (r = 0.359, P < 0.01), respectively.</p><p><b>CONCLUSIONS</b>The concentration of manganese in saliva could work as a biomarker of manganese internal exposure.</p>

Effect of Lycium barbarum polysaccharides on neurogenesis and learning & memory in manganese poisoning mice / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To study the effect of Lycium barbarum polysaccharides (LBP) on neurogenesis and learning & memory of manganese poisoning mice.</p><p><b>METHODS</b>Healthy adult Kunming mice were divided into 5 groups, the control group (A), the manganese poisoning (by manganese chloride peritoneal injection) group (B), the manganese poisoning and treated with gastric perfusion of high, medium, low dosage LBP groups (C, D and E). The spatial learning & memory capacity of mouse was determined by Morris water maze training test. The neurogenetic cells were labelled with bromodeoxyuridine (BrdU) and detected by immunohistochemistry.</p><p><b>RESULTS</b>The average escape latency was significantly higher and the times of passing through platform lower in group B than those in group A (P<0.05). BrdU positive cells in groups C, D and E were significantly more than those in group B (P<0.05).</p><p><b>CONCLUSION</b>LBP could enhance the learning & memory capability of the manganese poisoning mice by promoting neurogenesis in hippocampus.</p>

Manganese exposure and the neuropsychological effect on children and adolescents: a review / Exposición al manganeso y su efecto neurosicológico en niños y adolescentes: una revisión

OBJECTIVES: Manganese (Mn) is an essential element, but overexposure can have neurotoxic effects. METHODS: In this article, we review and summarize studies on exposure to Mn and nervous system impairments in children. RESULTS: We identified 12 original articles published between 1977 and 2007. Overexposure to Mn was suspected to occur through diverse sources: infant milk formula, drinking water, industrial pollution, and mining wastes. The most common bioindicator of exposure to Mn was hair Mn content, but some studies measured Mn in blood, urine, or dentin; one study on prenatal exposure measured Mn content in cord blood. Most studies indicate that higher postnatal exposure to Mn is associated with poorer cognitive functions and hyperactive behavior. CONCLUSIONS: The limitations of the existing studies are numerous: most were cross-sectional, had a modest sample size, and lacked adjustment for important confounders. Future investigations should be performed on a larger sample size and include a more detailed exposure assessment, addressing multiple sources of exposure such as food, water, and airborne particulates.

OBJETIVO: El manganeso (Mn) es un elemento esencial, pero la sobreexposición puede tener efectos neurotóxicos. MÉTODOS: En este artículo se hace una revisión y un compendio de los estudios publicados sobre la exposición al Mn y los trastornos del sistema nervioso en niños. RESULTADOS: Se identificaron 12 artículos originales publicados entre 1977 y 2007. La sobreexposición al Mn puede haber ocurrido a partir de diversas fuentes: leche en polvo o maternizada, agua de beber, polución industrial y desechos de la producción minera. El bioindicador de exposición utilizado con mayor frecuencia fue el contenido de Mn en el pelo, aunque algunos estudios lo midieron en la sangre, la orina o la dentina; un estudio sobre exposición prenatal midió su contenido en la sangre del cordón umbilical. La mayoría de los estudios indican que una mayor exposición posnatal al Mn se asocia con deficiencias en las funciones cognitivas y el comportamiento hiperactivo. CONCLUSIONES: Las limitaciones de los estudios publicados son numerosas: la mayoría de ellos eran transversales, se basaban en muestras pequeñas y en ellos no se ajustaron los resultados por importantes factores de confusión. Se requieren investigaciones adicionales con muestras mayores y que hagan una evaluación más detallada de la exposición, tomando en cuenta múltiples fuentes, como los alimentos, el agua y las partículas suspendidas en el aire.

Variations of brain magnetic resonance imaging among manganese-exposed workers / 中华预防医学杂志

<p><b>OBJECTIVE</b>Variations of the signal intensities in the magnetic resonance (MR) T(1)-weighted image (T(1)WI) of globus pallidus among manganese(Mn)-exposed workers were explored to provide a scientific basis for exposed biomarker of manganese-injured central nervous system (CNS).</p><p><b>METHODS</b>The brain MR T(1) and T(2) WI in eighteen male asymptomatic Mn-exposed, eight manganism and nine healthy control workers were examined routinely by adopting a 1.5 Tesla signal superconducting system. The SIGP and the signal intensity in frontal white matter (SIFWM) in the same side were determined, then pallidal index (PI) was calculated. Concentration of MnO(2) in workplaces and content of manganese in red blood cell (MnRBC) among workers were respectively determined by flame atomic absorption spectrometer (AAS) and inductively coupled plasma-atomic emission spectrophotometry (ICP-AES). The follow-up investigation in the eight high Mn-exposed workers was made one year later.</p><p><b>RESULTS</b>The results showed that the median of air MnO(2) in smelting workplace was 0.64 mg/m(3)(0.07 - 5.40 mg/m(3)), which were respective 0.56 mg/m(3)(0.09 - 1.71 mg/m(3)) in power distribution room (low Mn-exposure) and 0.89 mg/m(3) (0.07 - 5.40 mg/m(3)) in furnace (high Mn-exposure). PI in the Mn-exposed and high Mn-exposed workers were both higher than those of the manganism and control workers(116.4 +/- 8.2, 119.0 +/- 7.9, 105.3 +/- 8.4 and 102.2 +/- 1.5, respectively. Mn vs control, t' = 7.146, P = 0.000; Mn vs manganism, t = 3.181, P = 0.004. High Mn-exposure vs control, t' = 7.446, P = 0.000; high Mn-exposure vs manganism, t = 3.763, P = 0.001). The increased signal in T(1)WI of globus pallidus was observed in Mn-exposed workers, especially in high Mn-exposed workers. The content of manganese in red blood cell of Mn-exposed and control workers was significantly higher than those of the manganism workers [(151.6 +/- 40.5) ng/ml, (149.2 +/- 21.3) ng/ml, (154.5 +/- 46.6) ng/ml, (144.4 +/- 14.2) ng/ml, (20.8 +/- 7.4) ng/ml respectively. The difference was significant in statistics. Manganism vs control, t = 20.206, P = 0.000; manganism vs Mn, t' = 13.144, P = 0.000; manganism vs low and high Mn, t' = 12.964, 9.957, respectively, P = 0.000]. Only a decreased median of air MnO(2) in furnace was found one year later (0.89, 0.31 mg/m(3), Z = -2.142, P = 0.032). The difference was significant in statistics.</p><p><b>CONCLUSION</b>Our data suggests that SIGP of MR T(1)WI among workers was obviously increased by manganese-exposure. PI may be taken as the signal of CNS injury which was induced by manganese-exposure.</p>

Liver transplantion in a patient with rapid onset parkinsonism-dementia complex induced by manganism secondary to liver failure

Bilateral and symmetric globus-pallidus hyperintensities are observed on T1-weighted MRI in most of the patients with chronic liver failure, due to manganese accumulation. We report a 53-year-old man, with rapid onset parkinsonism-dementia complex associated with accumulation of manganese in the brain, secondary to liver failure. A brain MRI was performed and a high signal on T1-weighted images was seen on globus-pallidus, as well as on T2-weighted images on the hemispheric white-matter. He was referred to a liver-transplantation. The patient passed away on the seventh postoperative day. Our findings support the concept of the toxic effects of manganese on the globus-pallidus. The treatment of this form of parkinsonism is controversial and liver-transplantation should not be considered as first line treatment but as an alternative one.

Hiperintesidades simétricas e bilaterais dos gânglios da base são observadas em imagens de ressonância magnética encefálica (RM) ponderadas em T1 na maioria dos pacientes com insuficiência hepática crônica devidas ao acúmulo de manganês. Nós relatamos o caso de um homem, com 53 anos de idade, com um complexo parkinsonismo-demência rapidamente progressivo associado com o acúmulo de manganês no cérebro, secundariamente a insuficiência hepática. Uma RM encefálica foi realizada e foram observadas imagens hiperintensas/hipersinal nas imagens ponderadas em T1 no globo pálido e, também, na substância branca dos hemisférios cerebrais ponderadas em T2. Devido à falta de resposta ao tratamento clinico optamos pelo transplante hepático. O paciente faleceu no 7° dia de PO. Nossos achados corroboram o conceito dos efeitos tóxicos do manganês nos gânglios da base/globo pálido. O tratamento desta forma de parkinsonismo é controverso e o transplante hepático não deverá ser considerada uma opção terapêutica de primeira linha, porém como um tratamento alternativo considerando-se os riscos-benefícios dessa escolha.

Effects of manganismus on proliferation of neural stem cells in mice's hippocampus / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the effects of manganese poisoning on the proliferation of neural stem cells (NSCs) in mice's hippocampus.</p><p><b>METHODS</b>The mice (weight 8 approximately 10 g) were divided into control group(CG) low-dose group(LDG) middle-dose group(MDG) and high-dose group(HDG)by intraperitoneal injection of 0, 5, 20, 50 mg x kg(-1) x d(-1) of manganese chloride dissolved in physiological saline. The ability of learning and memory was detected by Morris Water Maze, and the proliferation of NSCs in subgranular zone (SGZ) in these mice's hippocampus was also detected by immunohistochemistry.</p><p><b>RESULTS</b>1) Compared with the CG, the ability of learning and memory in all manganism group decreased significantly (P < 0.01) and this phenomenon in HDG was most notable (P < 0.01). Meanwhile, the ability of memory was negatively correlated with the dose of manganese chloride (r(s) = -0.598, P < 0.01), but the difference of swimming speed in every group was of no statistic significance. (2) The numbers of NSCs in proliferation period in SGZ of all manganism groups was much lower than that of CG (P < 0.01) negatively correlated with the dose of manganese chloride (r(s) = -0.666, P < 0.01). (3) The reduction of NSCs had a positive correlation to the depression of learning and memory (r(s) = 0.734, P < 0.01).</p><p><b>CONCLUSIONS</b>Manganismus can affect the ability of learning and memory, which is probably caused by the inhalation of manganese on NSCs in hippocampus.</p>

Effects of manganese ions in the neuromuscular junction

The neurotoxic effects of manganese occured mainly from its inhalation are well described in the literature. In this study we have been demonstrated the potent and reversible effect of manganese ions (Mn²+) on neuromuscular transmission using conventional myographic. The Mn²+ mechanism wich causes reversible blockade at neuromuscular junction was investigated in isolated mouse phrenic nerve-diaphragm (PND) preparations. As much Mn²+ 0.9 mM as Mn²+ 1.8 mM produced rapid neuromuscular blockade (50% in < 4 min), but only the lower concentration reversed spontaneously. The use of d-tubocurarine (5.8 µM), 3,4-diaminopyridine 3,4-DAP, 0.09 mM) and dantrolene (10 µM) excluded the involvment of nicotinic receptors, K+ channels and ryanodine receptors, respectively, as the potential target for this ion. Manganese acts an early competitive antagonist and after as an agonist of Ca²+, indicating that this ion may probably act via Ca²+ cannels...