人造有毒化学物质 z-bo 2021-11-05 827

　　Neuroscientists at Georgetown University Medical Center say that man-made toxic chemicals that linger infinitely in the environment can damage the performance of key auxiliary cells in the mouse brain, resulting in impaired function after long-term exposure.

　　Their study is considered to be the first to test polychlorinated biphenyls (PCBs) in astrocytes, which are cells that support neurons and are vital to the homeostasis of the entire central nervous system . Studies have shown that this persistent environmental toxic substance may be a contributing factor in the development of astrocytes. Neurodegenerative diseases. They presented their findings at the annual meeting of the Society of Neuroscience in Chicago.

　　This research conducted in laboratory tests on mouse brain cells shows how the once widely used mixture of polychlorinated biphenyls opens up the pathways in astrocytes that try to neutralize toxins. The lead researcher of the study and PhD candidate of the Georgetown Neuroscience Interdisciplinary Program, Montoña McCann, said that many antioxidant genes known to be involved in human neurodegeneration are abnormally activated in mouse cells.

　　Research conducted by Mathann in the laboratory of Kathleen Maguire shows: "So far, our findings indicate that these toxins are closely related to the health of astrocytes. They also It helps us understand the importance of these astrocytes for maintaining brain function. Dr. Zeiss, Director of the Department of Neuroscience, Georgetown University.

　　These astrocytes can maintain the blood-brain barrier, support neurons, regulate the communication between neurons, and repair nerve tissue after injury and many other supportive tasks. She said: "If astrocytes fail, neurons will die. They are essential for maintaining the homeostasis (physiological stability) of the entire brain."

　　It is well known that PCBs can cause cancer, suppress the immune system, disrupt hormone signals and impair reproduction. In post-mortem studies, they were also associated with the death of substantia nigra brain cells (dopamine-producing cells) in Parkinson's disease patients.

　　Due to the stable chemical properties of PCB, heat resistance and electrical insulation, PCB is produced and widely used around the world, making it a coolant, flame retardant, lubricant, paint, adhesive and many other industrial products Ideal choice. Due to their toxicity, some countries began to ban their use in the 1970s and 1980s, but global production did not stop until 2001.

　　McCann said that the effects of these toxins continue. "The stability that makes PCBs so useful also allows them to persist in the environment."

　　In addition to several human diseases, PCBs have recently been associated with a decline in the number of killer whales. McCann suspects that the combination of environmental stressors (such as PCBs and genetic susceptibility factors) is related to neurodegeneration.

　　McCann said: "People in certain areas have been exposed to low-dose PCBs and other similar compounds for a long time in their lives." "Our laboratory research results show that this accumulation can lead to star glue. Plasma cells are oxidatively stressed and cannot support the neurons they maintain."

　　It is impossible for us to remove the accumulated PCBs from a person, but if human studies find specific pathways that are affected in the brain, "in the clinic, it is possible to compensate for the functional defects of astrocytes. It may be possible to compensate Mechanism to increase the ability of cells to buffer these toxic substances and promote survival," she said.

　　Maguire-Zeiss said: "The concept that environmental stress factors affect the health of astrocytes has not been fully studied."