The Anti-Inflammatory Drug Carprofen Improves Long-Term Outcome and Induces Gliogenesis after Traumatic Brain Injury Orli Thau-Zuchman, 1,2 Esther Shohami, 2 Alexander G. Alexandrovich, 2 Victoria Trembovler, 2 and Ronen R. Leker 1 Abstract Traumatic brain injury (TBI) initiates acute and chronic inflammatory processes involving cyclooxygenase-2 (COX-2), which may have detrimental effects on outcome and especially on brain regeneration. Therefore we aimed to study whether carprofen, a COX-2 inhibitor, would improve outcome and increase neurogenesis after TBI. TBI was induced in Sabra mice that were then treated with vehicle or carprofen for 7 days. Functional outcome was evaluated with the Neurological Severity Score (NSS).Cytokine levels were assessed 4 h post-TBI and water content was measured 24 h post TBI. Mice were given BrdU to label newborn cells for 10 days. The animals were killed 90 days post-TBI and the lesion size as well as newborn cell fate were assessed. Carprofen significantly reduced lesion size ( p = 0.002), decreased water content in the lesioned cortex ( p = 0.03), reduced the number of microglia in the lesioned cortex ( p < 0.0001), and lowered the levels of proinflammatory cytokines (IL- 1b, p = 0.03; IL-6, p = 0.02). Carprofen led to significantly larger improvements in functional outcome ( p £ 0.008) which were durable over 90 days. Carprofen also induced a threefold increase in the proliferation of new cells in the peri-lesion area ( p £ 0.002), but newborn cells differentiated mainly into glia in both groups. Carprofen is neuroprotective and induces cell proliferation and gliogenesis after TBI. Treatment with carprofen is consistently associated with better functional outcome. Our results imply that anti-inflammatory drugs may represent novel therapeutic options for TBI. Key words: angiogenesis; neurogenesis; neuroprotection; vascular endothelial growth factor; traumatic brain injury Introduction T raumatic brain injury (TBI) initiates complex pro- cesses and signaling changes that lead to pathological events, including increased blood–brain barrier (BBB) perme- ability leading to cerebral edema, and the release of prosta- glandins, free radicals, complement, and proinflammatory cytokines, as well as the induction of excitotoxicity, altered gene expression, and inflammation (Leker and Shohami, 2002). In particular, central nervous system (CNS) inflammation following TBI induces the proliferation of astrocytes and mi- croglia, leukocyte recruitment, and upregulation and secre- tion of mediators such as cytokines and chemokines that may also exacerbate tissue damage after injury (Kelsen et al., 2006; Leker and Shohami 2002; Stahel et al., 2000; Stoll et al., 2002; Yatsiv et al., 2002). Repair mechanisms based on pharmaco- logical interventions aimed at reducing the levels of primary inflammatory processes in the post-traumatic brain enable the survival of injured neurons (Kelsen et al., 2006; Leker and Shohami, 2002; Stahel et al., 2000; Stoll et al., 2002; Yatsiv et al., 2002). Reduction in the inflammatory brain response may also lead to an increase in newborn endogenous progenitor cells by producing a less hostile environment that allows them to proliferate and differentiate (Hoehn et al., 2005; Monje et al., 2003). The ensuing regenerative reactions in the brain can contribute to functional gains after TBI. Perturbation of arachidonic acid metabolism plays a significant role in normal and pathological responses. Fol- lowing TBI there is a massive accumulation of intracellular calcium, leading to arachidonic acid release from membrane phospholipids, and to the accumulation of prostaglandins (Shohami et al., 1987). The inducible enzyme cyclooxygenase-2 1 Department of Neurology and the Peritz and Chantal Scheinberg Cerebrovascular Research Laboratory, Hadassah-Hebrew University Medical Center and the 2 Institute of Drug Research (IDR), School of Pharmacy, the Hebrew University Jerusalem. JOURNAL OF NEUROTRAUMA 29:375–384 (January 20, 2012) ª Mary Ann Liebert, Inc. DOI: 10.1089/neu.2010.1673 375