T raumaTic brain injury (TBI) is a leading cause of death and disability worldwide. An estimated 75%-90% of the 1.7 million TBI-related emergency room visits in the US each year are a result of mild TBI (mTBI). 15 Unlike moderate and severe TBI, patients with mTBI may show cognitive impairment in the absence of obvious tissue lesions in the brain. 22,94 Some patients with mTBI have a measurable cognitive deficit at 1 year. 74 Recent evidence suggests that an mTBI sustained in early life can interact with the aging process and reduce memory performance many years or decades later. 69 The pathologies underlying mTBI are poorly understood and treatment modalities are essentially absent. Investigation of mechanisms underlying mTBI-induced cognitive impairment and development of effective early interventions to mitigate the sequelae of mTBI are required to better understand its pathophysiology and to reduce the burden and incidence of long-term effects of mTBI.abbreviatioNs APP = amyloid precursor protein; BrdU = 5′-bromo-2′-deoxyuridine; BSA = bovine serum albumin; DCX = doublecortin; GFAP = glial fibrillary acidic protein; MWM = Morris water maze; mTBI = mild TBI; NeuN = neuronal nuclei; PBS = phosphate-buffered saline; sAPPa = soluble a form of APP; TBI = traumatic brain injury. obJect Long-term memory deficits occur after mild traumatic brain injuries (mTBIs), and effective treatment modalities are currently unavailable. Cerebrolysin, a peptide preparation mimicking the action of neurotrophic factors, has beneficial effects on neurodegenerative diseases and brain injuries. The present study investigated the long-term effects of Cerebrolysin treatment on cognitive function in rats after mTBI. methods Rats subjected to closed-head mTBI were treated with saline (n = 11) or Cerebrolysin (2.5 ml/kg, n = 11) starting 24 hours after injury and then daily for 28 days. Sham animals underwent surgery without injury (n = 8). To evaluate cognitive function, the modified Morris water maze (MWM) test and a social odor-based novelty recognition task were performed after mTBI. All rats were killed on Day 90 after mTBI, and brain sections were immunostained for histological analyses of amyloid precursor protein (APP), astrogliosis, neuroblasts, and neurogenesis. results Mild TBI caused long-lasting cognitive memory deficits in the MWM and social odor recognition tests up to 90 days after injury. Compared with saline treatment, Cerebrolysin treatment significantly improved both long-term spatial learning and memory in the MWM test and nonspatial recognition memory in the social odor recognition task up to 90 days after mTBI (p < 0.05). Cerebrolysin significantly increased the number of neuroblasts and promoted neurogenesis in the dentate gyrus, and it reduced APP levels and astrogliosis in the corpus callosum, cortex, dentate gyrus, CA1, and CA3 regions (p < 0.05). coNclusioNs These results indicate that Cerebrolysin treatment of mTBI improves long-term cognitive function, and this improvement may be partially related to decreased...

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