engleski

Microglial activation after repetitive traumatic brain injury in the mouse

Introduction: Interest in repetitive traumatic brain injury (rTBI) has greatly increased because of its frequent occurrence in athletes engaged in contact sports, in military personnel and victims of domestic violence. Authors of numerous clinical studies suggested cumulative effects following rTBI and broad range of consequent short and long-term physical, cognitive, behavioral and emotional impairments. Only few experimental studies of rTBI have been published till today and pathophysiological events following repetitive brain trauma, and its neurobiology, are yet to be elucidated. The purpose of our study was to investigate the brain microglial reaction following rTBI in mice. Material and methods: rTBI of mild severity was induced on adult male C57BL/6 mice using the weight drop method described by Kane et al. (2012). Apparatus consisted of a vertical metal tube and a steel weight suspended on a nylon thread. Below the tube was a box with a piece of aluminum foil at its upper, open side to which the animals have been placed immediately after the induction of isoflurane anesthesia. Weight was set just above their head, between the ears, pulled rapidly upward to a height of 1 m above the mouse’s head, and released. rTBIs were performed twice daily, in the intervals of 6 h, during 5 consecutive days. Sham treated, control animals were anesthetized without receiving the brain injury. The mice were sacrificed at different time points after the last brain trauma induction or sham procedure and their brains were prepared for histological analyses. Microglia activation was determined by ionized calcium binding adaptor molecule 1 immunohistological labeling and examined using the fluorescence microscopy. Results: The density of transformed microglia cells characterized by shortening and widening of the processes, and also of those with amoeboid morphology, was higher in the brain regions of traumatized animals in relation to mice of the control group at the time points investigated. Conclusion: This preliminary study suggests the increased brain microglial activation following rTBI in the mouse.

repetitive traumatic brain injury; microglia; mouse

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