In a developing brain microglial cells are responsible for tasks such as phagocytosis, neuronal apoptosis, blood vessel formation, and synapse remodeling. Knowing that microglia play a role in pathology can help us determine how microglial cells can be used by means of therapy for neural injuries and diseases. In reference to the article, "Microglia: Key Elements in Neural Development, Plasticity, and Pathology", Eyo and Dailey examine the motility of microglial cells and cell to cell interactions between neurons and glia in vivo. They also mention how the transplantation of microglia can serve as a benefit to individuals with neural injuries or diseases.
Microglial cell movement was observed in the developing brain of a neonatal rat in the hippocampus. The microglia in this region of the isolated brain tissue slice moved toward the dead cells and engulfed them. The movement of the microglia facilitate the clearance of dead cells, after clearing the dead cells the microglia deactivate into a ramified state. Eyo and Dailey point out from another study that given a local injury in the adult cortex in vivo, microglial somata remain stationary for at least five hours (Eyo and Dailey, 2013). This differs from neonatal tissue in that it only takes about two hours before migratory microglia is seen. At the site of injury in an adult mouse the microglial branch tips extend toward the injury site. This would suggest that in early development microglial cells are migratory while in adulthood microglial cells are stationary with motile branches that extend to survey the surrounding area (Eyo and Dailey, 2013). Since microglia become stationary in adulthood they have a stronger interaction with other cells such as the extracellular matrix. However, it's unknown exactly how the extracellular matrix is related to microglial cells in development.
In Eyo and Dailey's article one neural disease they mention is Rett syndrome. It mainly affects females as it is known to affect the X chromosome. It's suspected that glial cells are what contribute to the neural abnormalities in Rett syndrome. Although, microglial transplantation aided in the improvement of life span, breathing, and motor function (Eyo and Dailey, 2013). Based on this finding it's possible that transplanting microglia can prove to be beneficial to those with neural diseases. Typically in ischemic strokes microglial cells are harmful and make the stroke worse. When microglia were implanted about four hours after the onset simulation ischemia significant neuroprotection was observed (Eyo and Dailey, 2013). This indicates that microglia due have the potential to aid in ischemia strokes if transplanted with a certain time frame.
An article, "Microglia in Central Nervous System Repair After Injury" by Xuemei Jin and Toshihide Yamashita explain how microglial cells have important inflammation functions like the removal of dead cells and functional recover of the CNS after injury in adult mammals. They mention how microglial cells can be beneficial and detrimental to the repairing of the CNS, much like how Eyo and Dailey mention that microglia can potentially worsen the effects of a stroke. The phagocytic ability of microglia to remove dead/damaged tissue after neural injury aids in axonal outgrowth which is important in development (Jin and Yamashita, 2016). This proves that microglia can repair some detrimental effects of a neural injury. Therefore, transplanting microglial cells to the site of said neural injury may actually be more beneficial. In this article it's also mentioned that motor neuron survival is improved by activated microglia and positive T-cells. This shows that microglia and T-cells work together to benefit post-injury CNS repair (Jin and Yamashita, 2016). This article in conjunction with Eyo and Dailey's show that microglial cells can play a crucial role in repairing and protecting affected tissue from neural injuries or diseases.
Works Cited
Eyo B, U. and Dailey M. E. "Microglia: Key Elements in Neural Development, Plasticity, and Pathology". 14 Jan. 2013. DOI: 10.1007/s11481-013-9434-z.
Xuiemei, J. and Yamashita, T. "Microglia in Central Nervous System Repair After Injury". 8 Feb. 2016. https://doi.org/10.1093/jb/mvw009.
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