Several million traumatic brain injury (TBI) events are reported in the United States annually. However, mild TBI events often go unreported, and mild and repetitive mild TBI conditions are challenging to model. Fruit flies (Drosophila melanogaster) have gained traction for the study of TBI. The best-characterized fly TBI model is the high-impact trauma (HIT) method. We replicated the HIT method and confirmed several previous findings at the standard level of injury severity. We then expanded upon the HIT model by characterizing mortality across three reduced levels of injury severity. Importantly, we found reduced mortality with reduced injury severity and synergistic effects on mortality in response to repetitive TBI by our moderate injury conditions. Last, we compared moderate, repetitive TBI to a single severe TBI via assessment of the pattern of mortality and geotaxis performance in the 24 h following TBI. We found the number and severity of injuries could result in different patterns of death, while all TBI conditions led to impaired geotaxis compared to uninjured flies at 0.5 h and 6 h post-TBI. Thus, we have extended a well-characterized model of TBI in flies, and shown the utility of this model for making unique insights into TBI across various severities, injury numbers, and time-points post-injury.

中文翻译：

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将飞行TBI模型扩展到四个级别的伤害严重程度，揭示了中度伤害条件下重复伤害的协同效应。

美国每年报告数百万次创伤性脑损伤（TBI）事件。但是，轻度TBI事件通常没有报道，轻度和重复性轻度TBI条件很难建模。对于TBI的研究，果蝇（果蝇（Drosophila melanogaster））已获得关注。最具特征的蝇类TBI模型是高冲击创伤（HIT）方法。我们重复了HIT方法，并在损伤严重程度的标准水平上确认了一些先前的发现。然后，我们通过描述三种降低的伤害严重程度的死亡率来扩展HIT模型。重要的是，我们发现由于中等程度的伤害条件而导致的重复性TBI导致死亡率降低，伤害严重性降低以及对死亡率的协同作用。最后，我们比较了中度 通过评估TBI后24小时内的死亡率和趋地性表现，可将重复性TBI转变为单个严重TBI。我们发现受伤的数量和严重程度可能导致不同的死亡方式，而在TBI后0.5小时和6小时，与未受伤的果蝇相比，所有TBI条件都导致地轴性受损。因此，我们在苍蝇中扩展了一个特征明确的TBI模型，并展示了该模型的实用性，它可以使TBI在各种严重性，损伤数和损伤后的时间点上获得独特的见解。