Study Of The Protective Effect Of Taurine On The Neurotoxicity Induced By Manganese In Vitro

Manganese(Mn) is a common neurtoxin. Though extrapyramidal dysfunction of neurodegenerative toxicity induced by occupational Mn exposure has been recognized widespread, its mechanism has been far from explicated and there is still not an ideal therapy. To explore its possible mechanism of neurotoxicity and find out a preventive factor, we study the morphological changes of neurone induced by Mn and the preventive effect of taurine(Tau)in vitro. Methods: Neurone primary cultures were prepared from cerebral cortex of neonatal Wistar rats. Cells were exposed to different concentrations of Mn and MTT assay was used to analysis neuronal viability. According to the result of MTT assay, three dose groups exposed to high, middle, and low level of Mn were set and ultrastructure changes were observed in each group with transmission electron microscope. Intoxication model was established with the lowest observed adverse effect level of Mn, then 0.5,1,2,4mmol/L of Tau were added. Control groups were set simultaneously. Supernatants or cells were collected to test the activity of lactate dehydrogenase and neuronal viability was observed with MTT assay after 24 hours. Concentration of malondialdehyde was determined and morphological changes were observed with light microscope, transmission electron microscope and scanning electron microscope. Result: Cell viability showed no decrease in the present of 0.1mM Mn. 0.4~8 Mm Mn concentration dependent induced cell viability decrease. Transmission electron microscope showed that the features of ultrastructure change were varied exposed to different concentration of Mn. Low dose of Mn(0.1mM) mainly cause Endoplasmic reticulum hyperplasia yet high dose(1mM)induce changes in lysosomes. The feature of apoptosis was shown chiefly in the group of middle dose of Mn(0.4mM). Tau showed no effect on cell viability in a short time exposure. 0.5mM Tau but not 1,2,4mM can inhibit cell viability decreasing and LDH activity increasing exposed to 0.4mM Mn for 24h. MDA concentration showed no significant change in each group. Morphological observation showed that the damage on Nissl bodies and cell membrane caused by Mn was relieved and the amount of apoptosis cells was also decreased after 0.5mM Tau was treated. Conclusion: Mn induced neurone death was concentration dependent. Characters of ultrastructure change were varies with Mn concentration. Proper dose of Tau had a protective effect on neurone against Mn and may related to its effect on cell membrane.