在活體外實驗中,過量的重金屬錳對於聽覺神經纖維和螺旋神經節神 經元以及耳蝸毛細胞是有毒性的,2011 年 Ding 和他的同事在神經毒 理學期刊發表的一項研究,首次顯示低濃度錳會損傷大鼠內耳的神經 元和感覺毛細胞。為了探討錳引起聽覺障礙的機制,我們評估不同劑 量的錳引起 ICR 小鼠的聽力障礙,以及對耳蝸病理損害的程度。本 研究採用聽覺腦幹誘發電位反應(ABR )記錄並且比較經過 5 次皮下 注射生理鹽水、低高劑量(10 毫克/公斤/日)或高劑量的氯化錳(50 毫克 /公斤/日) ICR 小鼠的聽覺閾值。本研究也採用免疫染色技術比較 ICR 小鼠的耳蝸內運動蛋白prestin 與凋亡蛋白cleavedcaspase-3的表達。 我們的研究結果顯示經過低和高劑量錳處理的 ICR 小鼠的 ABR 閾值 均較注射生理鹽水的 ICR 小鼠顯著增加;雖然外毛細胞的運動蛋白 prestin 表達在注射生理鹽水與錳處理的 ICR 小鼠差異不大,但是在低、 高劑量錳處理的 ICR 小鼠耳蝸內的外耳毛細胞、螺旋神經節神經元 以及血管紋細胞,均可以觀察到明顯的凋亡蛋白 cleaved caspase-3 表 達。因此,我們認為耳蝸細胞凋亡過程可能參與了錳誘導的聽覺損傷的作用。

In vitro, overdose of manganese is toxic to auditory nerve fibers as well as spiral ganglion neurons and cochlear hair cells. In 2011, Ding and his colleagues published a study in Neurotoxicology showing for the first time that low levels of manganese initially damage neurons and sensory hair cells in the inner ears of rats. To understand the mechanism for manganese-induced auditory impairment, we assessed the degree of hearing impairment and the cochlear histopathological damage in ICR mouse model resulting from various levels of manganese. The auditory brainstem response (ABR) recording was used to determine and compare the auditory threshold in ICR mice after 5 times subcutaneous injection of saline, low (10 mg/kg/day) or high dose (50 mg/kg/day) of manganese chloride. Immunochemistry staining techniques were used to compare expression of prestin, a cochlear motor protein, and cleaved caspase-3, a apoptosis protein, in the cochlea of ICR mice. Our results show that the ABR thresholds of ICR mice were significantly elevated with low and high dose of manganese treatments. Although the difference of prestin expression in outer hair cells was not observed among ICR mice with subcutaneous injection of saline, low and high dose of manganese. The apoptosis-related cleaved caspase-3 was obviously observed in outer hair cells, spiral ganglion neurons, and stria vascularis cells in the cochlea of ICR mice with subcutaneous injection low and high dose of manganese.
Thus we suggest that the cochlear apoptosis may be involved in manganese-induced auditory impairment.

Antonini JM, Roberts JR, Stone S et al. Short-term inhalation exposure to mild steel welding fume had no effect on lung inflammation and injury but did alter defense responses to bacteria in rats. Inhal Toxicol. 2009;21:182–192.

Antonini JM, Sriram K, Benkovic SA et al. Mild steel welding fume causes manganese accumulation and subtle neuroinflammatory changes but not overt neuronal damage in discrete brain regions of rats after short-term inhalation exposure. Neurotoxicology. 2009;30:915–925.

Au C, Benedetto A, Aschner M. Manganese transport in eukaryotes: the role of DMT1. Neurotoxicology. 2008;29:569–576.

Barbeau A. Manganese and extrapyramidal disorders (a critical review and tribute to Dr. George C. Cotzias). Neurotoxicology. 1984;5:13-35.

Bespalova IN, Van Camp G, Bom SJ et al. Mutations in the Wolfram syndrome 1 gene (WFS1) are a common cause of low frequency sensorineural hearing loss. Hum Mol Genet. 2001;10:2501–2508.

Bouchard M, Laforest F, Vandelac L et al. Hair manganese and hyperactive behaviors: pilot study of school-age children exposed through tap water. Environ Health Perspect. 2007;115:122–127.

Bouchard M, Mergler D, Baldwin ME et al. Manganese cumulative exposure and symptoms: a follow-up study of alloy workers. Neurotoxicology. 2008;29:577–583.

Bourre JM. Effects of nutrients (in food) on the structure and function of the nervous system: update on dietary requirements for brain. Part 1. Micronutrients. J Nutr Health Aging. 2006;10:377–385.

Bowler RM, Roels HA, Nakagawa S et al. Dose-effect relationships between manganese exposure and neurological, neuropsychological and pulmonary function in confined space bridge welders. Occup Environ Med. 2007;64:167–177.

Cheatham MA, Low-Zeddies S, Naik K et al. A chimera analysis of prestin knock-out mice. J Neurosci. 2009;29:12000–12008.

Chillrud SN, Epstein D, Ross JM et al. Elevated airborne exposures of teenagers to manganese, chromium, and iron from steel dust and New York City’s subway system. Environ Sci Technol. 2004;38:732-737.

Cotzias GC. Manganese in health and disease. Physiol Rev. 1958;38:503-532.

Couper J. On the effects of black oxide of manganese when inhaled into the lungs. Br Ann Med Pharmacol. 1837;1:41-42.

Dallos P, Wu X, Cheatham MA et al. Prestin-based outer hair cell motility is necessary for mammalian cochlear amplification. Neuron. 2008;58:333–339.

Degoul F, Nelson I, Lestienne P et al. Deletions of mitochondrial DNA in Kearns-Sayre syndrome and ocular myopathies: genetic, biochemical and morphological studies. J Neurol Sci. 1991;101:168–177.

Desole MS, Esposito G, Migheli R et al. Cellular defence mechanisms in the striatum of young and aged rats subchronically exposed to manganese. Neuropharmacology. 1995;34:289–295.

Ding D, Roth J, Salvi R. Manganese is toxic to spiral ganglion neurons and hair cells in vitro. NeuroToxicology. 2011;32:233–241.

Emmerer AR, Elvehjem CA, Hart EB. Studies on the relation of manganese to the nutrition of the mouse. J Biol Chem. 1931;92:623–630.

Erikson KM, Dorman DC, Lash LH et al. Duration of airborne- manganese exposure in rhesus monkeys is associated with brain regional changes in biomarkers of neurotoxicity. Neurotoxicology. 2008;29:377– 385.

Finley JW. Does environmental exposure to manganese pose a health risk to healthy adults? Nutrit Rev. 2004;62:148-153.

Fox SI. Human physiology. McGraw-Hill Higher Education. 2008;10e:269-280.

Fujinami Y, Mutai H, Mizutari K et al. A novel animal model of hearing loss caused by acute endoplasmic reticulum stresss in the cochlea. J Pharmacol Sci. 2012;118:363-372.

Gavin CE, Gunter KK, Gunter TE. Manganese and calcium efflux kinetics in brain mitochondria. Relevance to manganese toxicity. Biochem J. 1990;266:329–334.

Gold M and Rapin I. Non-Mendelian mitochondrial inheritance as a cause of progressive genetic sensorineural hearing loss. Int J Pediatr Otolaryngol. 1994;30:91–104.

Gonzalez-Zulueta M, Ensz LM, Mukhina G et al. Manganese superoxide dismutase protects nNOS neurons from NMDA and nitric oxide-mediated neurotoxicity. J Neurosci. 1998;18:2040–2055.

Goto Y, Horai S, Matsuoka T et al. Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS): a correlative study of the clinical features and mitochondrial DNA mutation. Neurology. 1992;42:545–550.

Gunter TE, Miller LM, Gavin CE et al. Determination of the oxidation states of manganese in brain, liver, and heart mitochondria. J Neurochem. 2004;88:266–280.

Gupta SK, Murthy RC, Chandra SV. Neuromelanin in manganese-exposed primates. Toxicol Lett. 1980;6:7-20.

Gwiazda R, Lucchini R, Smith D. Adequacy and consistency of animal studies to evaluate the neurotoxicity of chronic low-level manganese exposure in humans. J Toxicol Environ Health A. 2007;70:594–605.

Hazell AS, Normandin L, Norenberg MD et al. Alzheimer type II astrocytic changes following sub-acute exposure to manganese and its prevention by antioxidant treatment. Neurosci Lett. 2006;396:167–171.

Hutchin TP and Cortopassi GA. Mitochondrial defects and hearing loss. Cell Mol Life Sci. 2000;57:1927–1937.

Ingersoll RT, Montgomery EB, Aposhian HV. Central nervous system toxicity of manganese. Fundamental And Applied Toxicology 1995;27:106–113.

Inoue H, Tanizawa Y, Wasson J et al. A gene encoding a transmembrane protein is mutated in patients with diabetes mellitus and optic atrophy (Wolfram syndrome). Nat Genet. 1998;20:143–148.

Josephs KA, Ahlskog JE, Klos KJ et al. Neurologic manifestations in welders with pallidal MRI T1 hyperintensity. Neurology. 2005;64:2033–2039.

Kalliomaki PL, Tuomisaari M, Lakomaa EL et al. Retention and clearance of stainless steel shieldgas welding fumes in rat lungs. Am Ind Hyg Assoc J. 1983;44:649–654.

Katsoyiannis IA, Katsoyiannis AA. Arsenic and other metal contamination of groundwaters in the industrial area of Thessaloniki, Northern Greece. Environ Monit Assess. 2006;123:393–406.

Keen CL, Ensunsa JL, Clegg MS. Manganese metabolism in animals and humans including the toxicity of manganese. Met Ions Biol Syst. 2000;37:89–121.

Keen CL, Ensunsa JL, Watson MH et al. Nutritional aspects of manganese from experimental studies. Neurotoxicology. 1999;20:213–223.

Kwik-Uribe C, Smith DR. Temporal responses in the disruption of iron regulation by manganese. J Neurosci Res. 2006;83:1601–1610.

Liberman MC, Gao J, He DZ et al. Prestin is required for electromotility of the outer hair cell and for the cochlear amplifier. Nature. 2002;419: 300–304.

Ma C, Schneider SN, Miller M et al. Manganese Accumulation in the Mouse Ear Following Systemic Exposure. J Biochem Mol Toxicol. 2008;22:305–310.

McCord JM. Iron- and manganese-containing superoxide dismutases: structure, distribution, and evolutionary relationships. Adv Exp Med Biol. 1976;74:540–550.

Milatovic D, Zaja-Milatovic S, Gupta RC, Yu Y et al. Oxidative damage and neurodegeneration in manganese-induced neurotoxicity. Toxicol Appl Pharmacol. 2009;240:219– 225.

Moller, A.R. Hearing: Anatomy, Physiology, and Disorders of the Auditory System, second edition. Elsevier, Oxford, UK. 2006;pp.163-170.

Myers JE, Fine J, Ormond-Brown D et al. Estimating the prevalence of clinical manganism using a cascaded screening process in a South African manganese smelter. Neurotoxicology. 2009;30:934–940.

Myers JE, teWaterNaude J, Fourie M, Zogoeh B et al. Nervous system effects of occupational manganese exposure on South African manganese mineworkers. Neurotoxicology. 2003;24:649–656.

Nikolov Z. Hearing reduction caused by manganese and noise. JFORL J Fr Otorhinolar- yngol Audiophonol Chir Maxillofac. 1974;23:231–234.

Normandin L, Hazell AS. Manganese neurotoxicity: an update of pathophysiologic mechanisms. Metab Brain Dis. 2002;17:375–387.

Olanow CW, Good PF, Shinotoh H et al. Manganese intoxication in the rheusus monkey: a clinical, imaging, pathologic and biochemical study. Neurology. 1996;46:492-498.

Oliver D, He DZ, Klocker N et al. Intracellular
anions as the voltage sensor of prestin, the outer hair cell motor protein. Science. 2001;292:2340–2343.

Orent ER, McCollum EV. Effects of deprivation of manganese in the rat. J Biol Chem. 1931;92:661–678.

Pal PK, Samii A, Calne DB. Maganese neurotoxicity: a review of clinical features, imaging and pathology. NeuroToxicology. 1999;20:227-238.

Park JD, Kim KY, Kim DW et al. Tissue distribution of manganese in iron-sufficient or iron-deficient rats after stainless steel welding- fume exposure. Inhal Toxicol. 2007;19:563–572.

Park RM, Bowler RM, Roels HA. Exposure-response relationship and risk assessment for cognitive deficits in early welding-induced manganism. J Occup Environ Med. 2009;51:1125–1136.

Peter D, Xudong Wu, Mary Ann Cheatham et al. Prestin-based outer hair cell motility is necessary for mammalian cochlear amplification. Neuron. 2008;58(3):333–339.

Rajagopalan L, Greeson JN, Xia A et al. Tuning of the outer hair cell motor by membrane cholesterol. J Biol Chem. 2007;282:36659–36670.

Rajagopalan L, Organ-Darling LE, Liu H et al. Glycosylation regulates prestin cellular activity. J Assoc Res Otolaryngol. 2010;11:39–51.

Rama Rao KVR, Reddy PVB, Hazell AS et al. Manganese induces cell swelling in cultured astrocytes. Neurotoxicology. 2007;28:807–812.

Rose C, Butterworth RF, Zayed J, Normandin L et al. Manganese deposition in basal ganglia structures results from both portal-systemic shunting and liver disfunctyon. Gastroenterology. 1999;117:640–644.

Ruebhausen MR, Brozoski TJ, Bauer CA. A comparison of the effects of isoflurane and ketamine anesthesia on auditory brainstem response (ABR) thresholds in rats. Hearing Research. 2012;287:25-29.

Santos-Sacchi J, Song L, Zheng J et al. Control of mammalian
cochlear amplification by chloride anions. J Neurosci. 2006;26:3992–3998.

Schaechinger TJ and Oliver D. Nonmammalian orthologs of prestin 
(SLC26A5) are electrogenic divalent/chloride anion exchangers. Proc Natl Acad O
Sci U S A. 2007;104:7693–7698.

Seidman MD, Quirk WS and Shirwany NA. Mechanisms of alterations in the microcirculation of the cochlea. Ann NY Acad Sci. 1999;884:226–232.

Sfondouris J, Rajagopalan L, Pereira FA et al. Membrane composition modulates prestin-associated charge movement. J Biol Chem. 2008;283:22473–22481.

Sistrunk SC, Ross MK, Filipov NM. Direct effects of manganese compounds on dopamine and its metabolite Dopac: An in vitro study. Environ Toxicol Pharmacol. 2007;23:286–296.

Uy J, Forciea MA. In the clinic. Hearing loss. Ann intern Med. 2013;158:ITC4

Von JR. Veber mangantoxikosen und manganophobie. Munch Med Wochenschr. 1907;20:969-972.

Wangemann P, Liu J, Marcus DC. Ion transport mechanisms response for K+ secretion and the transepithelial voltage across marginal cells of stria vascularis in vitro. Hearing Research. 1995;84:19-29.

Wedler FC, Denman RB. Glutamine synthetase: the major Mn(II) enzyme in mammalian brain. Curr Top Cell Regul. 1984;24:153–169.

William E. Brownell, Ph.D. How the ear works – nature’s solutions for listening. Volta Rev. 1997;99:9–28.

Willott JF. Measurement of the auditory brainstem response (ABR) to study auditory sensitivity in mice. Curr Protoc Neurosci. 2006;Unit 8.21B:chapter 8.

Xia A, Song Y, Wang R et al. Prestin regulateon and function in residual outer hair cells after noise-induced hearing loss. PLoS ONE. 2013;8:e82602.

Yamada M, Ohno S, Okagasy I et al. Chronic manganese poisoning: a neuropathological study with determination of manganese distribution in the brain. Acta Neuropathol (Berl). 1986;71:723-728.

Yang SY, Chen CY, Lee LH et al. New frontier in health effects of welding fume. Journal of Occupational Safety and Health. 2012;20:394-407.

Yin Z, Aschner JL, dos Santos AP et al. Mitochondrial-dependent manganese neurotoxicity in rat primary astrocyte cultures. Brain Res. 2008;1203:1–11.

Yin Z, Jiang H, Lee ES, Ni M et al. Ferroportin is a manganese- responsive protein that decreases manganese cytotoxicity and accumulation. J Neurochem. 2010;112:1190–1198.

Zhang F, Xu Z, Gao J, Xu B et al. In vitro effect of manganese chloride exposure on energy metabolism and oxidative damage of mitochondria isolated from rat brain. Environ Toxicol Pharmacol. 2008;26:232–236.

Zhang S, Fu J, Zhou Z. In vitro effect of manganese chloride exposure on reactive oxygen species generation and respiratory chain complexes activities of mitochondria isolated from rat brain. Toxicol In Vitro. 2004;18:71–77.

Zhao F, Cai T, Liu M, Zheng G et al. Manganese induces dopaminergic neurodegeneration via microglial activation in a rat model of manganism. Toxicol Sci. 2009;107:156–164.

Zheng J, Shen W, He DZ et al. Prestin is the motor protein of cochlear outer hair cells. Nature. 2000;405:149–155.

林至欣醫生。關於內耳傷害引起之聽力喪失。高醫醫訊月刊 2001;20:10.