Traumatic brain injury (TBI) induces both focal and diffuse lesions that are concurrently responsible for the ensuing morbidity and mortality and for which no established treatment is available. It has been recently reported that an endogenous neuroprotector, the soluble form α of the
amyloid precursor
protein (sAPPα), exerts
neuroprotective effects following TBI. However, the emergent post-traumatic neuroinflammatory environment compromises sAPPα production and may promote neuronal degeneration and consequent brain
atrophy. Hence, the aim of this study was to examine the effects of the anti-inflammatory
drug minocycline on sAPPα levels, as well as on long-term histological consequences post-TBI. The weight-drop model was used to induce TBI in mice.
Minocycline or its vehicle were administered three times: at 5 min (90 mg/kg, i.p.) and at 3 and 9 h (45 mg/kg, i.p.) post-TBI. The levels of sAPPα, the extent of brain
atrophy, and reactive
gliosis were evaluated by ELISA,
cresyl violet, and immunolabeling of GFAP and CD11b, respectively. Our results revealed a post-TBI sAPPα decrease that was significantly attenuated by
minocycline. Additionally, corpus callosum and striatal
atrophy, ventriculomegaly,
astrogliosis, and microglial activation were observed at 3 months post-TBI. All the above consequences were significantly reduced by
minocycline. In conclusion, inhibition of the acute phase of post-TBI
neuroinflammation was associated with the sparing of sAPPα and the protection of brain tissue in the long-term, emphasizing the potential role of
minocycline as an effective treatment for TBI.