Toll-like receptor 4 contributes to poor outcome after intracerebral hemorrhage.

Objective: Intracerebral hemorrhage (ICH) is a devastating stroke subtype in which perihematomal inflammation contributes to neuronal injury and functional disability. Histologically, the region becomes infiltrated with neutrophils and activated microglia followed by neuronal loss, but little is known about the immune signals that coordinate these events. This study aimed to determine the role of Toll-like receptor 4 (TLR4) in the innate immune response after ICH and its impact on neurobehavioral outcome.

Autologous blood injection to model spontaneous intracerebral hemorrhage in mice.

Investigation of the pathophysiology of injury after intracerebral hemorrhage (ICH) requires a reproducible animal model. While ICH accounts for 10-15% of all strokes, there remains no specific effective therapy. The autologous blood injection model in mice involves the stereotaxic injection of arterial blood into the basal ganglia mimicking a spontaneous hypertensive hemorrhage in man.

Incorporation of pseudouridine into mRNA yields superior nonimmunogenic vector with increased translational capacity and biological stability.

In vitro-transcribed mRNAs encoding physiologically important proteins have considerable potential for therapeutic applications. However, in its present form, mRNA is unfeasible for clinical use because of its labile and immunogenic nature. Here, we investigated whether incorporation of naturally modified nucleotides into transcripts would confer enhanced biological properties to mRNA.

Cerebral preconditioning using cortical application of hypertonic salt solutions: upregulation of mRNAs encoding inhibitors of inflammation.

Previous studies have demonstrated that local application of hypertonic KCl or NaCl to the cerebral cortex induces tolerance to a subsequent episode of ischemia. The objective of the present study was to determine whether application of these salts increases the levels of mRNAs encoding inhibitors of inflammation. Hypertonic KCl or NaCl was applied for 2 h to the frontal cortex of Sprague-Dawley rats.

Inhibition of toll-like receptor and cytokine signaling--a unifying theme in ischemic tolerance.

Cerebral ischemia triggers acute inflammation, which exacerbates primary brain damage. Activation of the innate immune system is an important component of this inflammatory response. Inflammation occurs through the action of proinflammatory cytokines, such as TNF, IL-1 beta and IL-6, that alter blood flow and increase vascular permeability, thus leading to secondary ischemia and accumulation of immune cells in the brain.

Induction of tolerance to focal ischemia in rat brain: dissociation between cortical lesioning and spreading depression.

Cortical application of KCl has previously been shown to induce tolerance to a subsequent episode of cerebral ischemia. KCl triggers recurrent episodes of cortical spreading depression and produces a small lesion at the cortical application site. To determine whether a cortical lesion alone is sufficient to induce tolerance to ischemia, the authors used 5-mol/L NaCl to precondition rat brain 3 days before permanent occlusion of the middle cerebral artery.

Traumatic brain injury elevates glycogen and induces tolerance to ischemia in rat brain.

Previous studies have demonstrated that traumatic brain injury (TBI) increases the vulnerability of the brain to an acute episode of hypoxia-ischemia. The objective of the present study was to determine whether TBI alters the vulnerability of the brain to a delayed episode of ischemia and, if so, to identify contributing mechanisms. Sprague-Dawley rats were subjected to lateral fluid-percussion (FP) brain injury (n = 14) of moderate severity (2.

Structural and functional damage sustained by mitochondria after traumatic brain injury in the rat: evidence for differentially sensitive populations in the cortex and hippocampus.

The cellular and molecular pathways initiated by traumatic brain injury (TBI) may compromise the function and structural integrity of mitochondria, thereby contributing to cerebral metabolic dysfunction and cell death. The extent to which TBI affects regional mitochondrial populations with respect to structure, function, and swelling was assessed 3 hours and 24 hours after lateral fluid-percussion brain injury in the rat. Significantly less mitochondrial protein was isolated from the injured compared with uninjured parietotemporal cortex, whereas comparable yields were obtained from the hippocampus.

Cortical spreading depression causes a long-lasting decrease in cerebral blood flow and induces tolerance to permanent focal ischemia in rat brain.

Cortical spreading depression (CSD) has previously been shown to induce tolerance to a subsequent episode of transient cerebral ischemia. The objective of the present study was to determine whether CSD also induces tolerance to permanent focal ischemia and, if so, whether tolerance may be mediated by alterations in cerebral blood flow (CBF). Sprague-Dawley rats were preconditioned by applying potassium chloride to one hemisphere for 2 hours, evoking 19 +/- 5 episodes of CSD (mean +/- SD, n = 19).