Lentivirally administered glial cell line-derived neurotrophic factor promotes post-ischemic neurological recovery, brain remodeling and contralesional pyramidal tract plasticity by regulating axonal growth inhibitors and guidance proteins.

Owing to its potent longterm neuroprotective and neurorestorative properties, glial cell line-derived neurotrophic factor (GDNF) is currently studied in neurodegenerative disease clinical trials. However, little is known about the longterm effect of GDNF on neurological recovery, brain remodeling and neuroplasticity in the post-acute phase of ischemic stroke. In a comprehensive set of experiments, we examined the effects of lentiviral GDNF administration after ischemic stroke. GDNF reduced neurological deficits, neuronal injury, blood-brain barrier permeability in the acute phase in mice. As compared with control, enhanced motor-coordination and spontaneous locomotor activity were noted in GDNF-treated mice, which were associated with increased microvascular remodeling, increased neurogenesis and reduced glial scar formation in the peri-infarct tissue. We observed reduced brain atrophy and increased plasticity of contralesional pyramidal tract axons that crossed the midline in order to innervate denervated neurons in the ipsilesional red and facial nuclei. Contralesional axonal plasticity by GDNF was associated with decreased abundance of the axonal growth inhibitors brevican and versican in contralesional and ipsilesional brain tissue, reduced abundance of the growth repulsive guidance molecule ephrin b1 in contralesional brain tissue, increased abundance of the midline growth repulsive protein Slit1 in contralesional brain tissue and reduced abundance of Slit1's receptor Robo2 in ipsilesional brain tissue. These data indicate that GDNF potently induces longterm neurological recovery, peri-infarct brain remodeling and contralesional neuroplasticity, which are associated with the fine-tuned regulation of axonal growth inhibitors and guidance molecules that facilitate the growth of contralesional corticofugal axons in the direction to the ipsilesional hemisphere.

Allyl isothiocyanate attenuates oxidative stress and inflammation by modulating Nrf2/HO-1 and NF-κB pathways in traumatic brain injury in mice.

Traumatic brain injury (TBI) is the leading cause of mortality and morbidity in young adults and children in the industrialized countries; however, there are presently no FDA approved therapies. TBI results in oxidative stress due to the overproduction of reactive oxygen species and overwhelming of the endogenous antioxidant mechanisms. Recently, it has been reported that antioxidants including phytochemicals have a protective role against oxidative damage and inflammation after TBI. To analyze the effects of a naturally occurring antioxidant molecule, allyl isothiocyanate (AITC), on the nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor kappa B (NF-κB) signaling pathways in TBI, a cryogenic injury model was induced in mice. Here, we showed that AITC administered immediately after the injury significantly decreased infarct volume and blood-brain barrier (BBB) permeability. Protein levels of proinflammatory cytokines interleukin-1ß (IL1ß) and interleukin-6 (IL6), glial fibrillary acidic protein (GFAP) and NF-κB were decreased, while Nrf2, growth-associated protein 43 (GAP43) and neural cell adhesion molecule levels were increased with AITC when compared with vehicle control. Our results demonstrated that the antioxidant molecule AITC, when applied immediately after TBI, provided beneficial effects on inflammatory processes while improving infarct volume and BBB permeability. Increased levels of plasticity markers, as well as an antioxidant gene regulator, Nrf2, by AITC, suggest that future studies are warranted to assess the protective activities of dietary or medicinal AITC in clinical studies.

Cinnamon Polyphenol Extract Exerts Neuroprotective Activity in Traumatic Brain Injury in Male Mice.

BACKGROUND: Cinnamon polyphenol extract is a traditional spice commonly used in different areas of the world for the treatment of different disease conditions which are associated with inflammation and oxidative stress. Despite many preclinical studies showing the anti-oxidative and antiinflammatory effects of cinnamon, the underlying mechanisms in signaling pathways via which cinnamon protects the brain after brain trauma remained largely unknown. However, there is still no preclinical study delineating the possible molecular mechanism of neuroprotective effects cinnamon polyphenol extract in Traumatic Brain Injury (TBI). The primary aim of the current study was to test the hypothesis that cinnamon polyphenol extract administration would improve the histopathological outcomes and exert neuroprotective activity through its antioxidative and anti-inflammatory properties following TBI. METHODS: To investigate the effects of cinnamon, we induced brain injury using a cold trauma model in male mice that were treated with cinnamon polyphenol extract (10 mg/kg) or vehicle via intraperitoneal administration just after TBI. Mice were divided into two groups: TBI+vehicle group and TBI+ cinnamon polyphenol extract group. Brain samples were collected 24 h later for analysis. RESULTS: We have shown that cinnamon polyphenol extract effectively reduced infarct and edema formation which were associated with significant alterations in inflammatory and oxidative parameters, including nuclear factor-κB, interleukin 1-beta, interleukin 6, nuclear factor erythroid 2-related factor 2, glial fibrillary acidic protein, neural cell adhesion molecule, malondialdehyde, superoxide dismutase, catalase and glutathione peroxidase. CONCLUSION: Our results identify an important neuroprotective role of cinnamon polyphenol extract in TBI which is mediated by its capability to suppress the inflammation and oxidative injury. Further, specially designed experimental studies to understand the molecular cross-talk between signaling pathways would provide valuable evidence for the therapeutic role of cinnamon in TBI and other TBI related conditions.