Studies On The Mechanism Of Manganese-induced Apoptosis Of Neuron In The Chicken Brain

Manganese(Mn) is a light gray transitional tungsten, it is widely used in industrial and agricultural production, such as dry cell batteries, metal pencils, sterilizing agents and chemical fertilizer. As an major enviromental and industrial pollutants, excessive manganese disturbs nervous function , liver function and lung function and results in manganism. Brain is the main target organ of manganism. In recent years, most of the studies focus on the rodent and human being, whlie only a few focus on the poultry. This study took the primary neuron in the chicken brain as a model. Neurons were cultivated in the DMEM for 24 h with the final concentration of MnCl₂ (0, 1.5, 2, 2.5 mmol/L). In order to study the mechanism of maganese-induced apoptosis of the neuron in chicken brain, some items about the activity of cell, apoptosis, mitochondrial respiratory function, oxygen stress, calcium homeostasis and the expression level of CaM mRNA andα-syn in the neuron were detected. The results showed as follows:1. Applying Nissl body staining, AO/EB double fluorescence coloration, transmission electron microscope, DNA Ladder, TUNEL and flow cytometry assay to detect appotosis induced by manganese in neurons. The results showed that MnCl₂ could induce apoptosis of the chinken embryonic neurons with dose-effect relation.2. Manganese induced the oxidative stress of neuron, decreased the content of GSH, and increased the content of ROS, and destroyed antioxidative defense system of neuron, remove the free radical . The results showed that MnCl₂ could couse oxidative damage in the neuron of the chicken.3. The activity of mitochondrial respiratory chain complex (I, II, III, IV and V ) andΔψm decresed. It hinted that excessive manganese could induce the damage of mitochondria and the disturbance of energy metabolism.4. Manganese increased the calcium ion concentration within neurons ([Ca²⁺]_i) and decreased the expression of CaM mRNA. This indicated that manganese could induce disequilibrium of calcium homeostasis.5. Manganese decreased the expression ofα-syn mRNA, then the result hinted that the neurotoxicity of manganese could induce the change ofα-syn.It was concluded that manganism can change the morphostructure of the chinken embryonic neurons and inhabit the activity of mitochondrial respiratory chain complex, induce oxidative stesss, cause disequilibrium of calcium homeostasis, induce the apoptosis of neurons. It included that manganese can cause the damage of neuron in the chicken brain.