IFN- also has been reported to have the inhibitory effect on oligodendroglial lineage cell proliferation and differentiation in vitro [32, 33]. differences between rUCCAO group and sham group intended for the expression of glutamate transporter-1 (GLT-1) and glutamate/aspartate transporter (GLAST). Furthermore, carnosine significantly attenuated the increase of inflammatory cytokine interferon gama. Bottom line: These data suggest carnosine induced neuroprotection during SIVD in mice is not dependent on the histaminergic pathway or the regulation of the expression of GLT-1 and GLAST, but may be due to a suppression of astrocyte activation and inflammatory cytokine release. Keywords: Astrocyte, carnosine, subcortical ischemic vascular dementia, white matter injury, interferon gama == Introduction == Subcortical ischemic vascular dementia (SIVD) induced by chronic hypoperfusion due to small-artery disease is a common cause for vascular dementia (VaD), which is recognized as the second most prevalent type of dementia [1]. Its characteristic damage contains progressive demyelination, white matter rarefaction, cognitive impairment, glial activation and oligodendrocyte deficiency [2]. However , pathogenetic mechanisms of SIVD are far from comprehended. The therapy of SIVD has received extensive attention and there are several compounds with different mechanisms showing mild efficacy in SIVD patients [3]. Up to now no drug has been approved to potentially prevent the progress of SIVD [4]. Astrocytes, because of their diverse and significant roles, especially in glutamatergic Terutroban signaling regulation in VaD, have become the focus of attention [5]. In recent years, it has Terutroban been shown that glutamate can be toxic to white matter oligodendrocytes and to myelin by sustained activation of glutamate receptors [6]. A line of study demonstrated that astrocytes play an Terutroban important role in maintaining low extracellular glutamate levels and eliminating and recycling glutamate in brain. Astrocytic glutamate transporter-1 (GLT-1) and glutamate/aspartate transporter (GLAST) are the primary controllers of extracellular glutamate levels in brain [7]. The inhibition of GLT-1 and/or GLAST by pharmacological blockers, antisense oligonucleotides or transgenic knockout elevates extracellular glutamate levels and induces neuronal death [8, 9], which may also affect the oligodendrocytes after hypotension. In addition , astrocytes release inflammatory cytokines and activate metalloproteases that contribute to blood-brain barrier disruption after ischemia [10]. Although the exact cause of white matter lesion after SIVD has not been conclusively established, white matter lesions possess frequently been suggested to have the relationship with glia activation [11]. Activated astrocyte is the major sources of proinflammatory cytokines, including TNF-, IL-6 and IFN-, which may result in the Mouse monoclonal to GLP degeneration of myelin and apoptosis of oligodendrocyte [12]. This evidence suggests that astrocyte plays an important role in SIVD. Carnosine (b-alanyl-L-histidine) is a natural dipeptide that is highly expressed in the central nervous system, and can easily enter the brain from the periphery. Carnosine can converse to histidine and then histamine, and serves as a non-mast-cell reservoir for histamine [13]. Many evidences suggest that histaminergic neurotransmission plays an important role in brain ischemia. Carnosine ameliorates acute renal failure induced by ischemia/reperfusion in rats and NMDA-induced excitotoxic injury in differentiated PC12 cells through its conversion to histidine and histamine [14]. Besides it has been assigned many putative roles, such as anti-inflammatory agent, free radical scavenger and mobile organic pH buffer. Carnosine protects against SIVD induced by permanent occlusion from the right unilateral common carotid arteries (rUCCAO) through its antioxidative effect [15]. However , few reports have demonstrated significant relations between brain carnosine/histamine and astrocyte function in SIVD. Therefore , we investigated the effect of carnosine on astrocyte function in SIVD induced by rUCCAO and whether its action involves the histaminergic pathway. == Materials and methods == == Animal preparation == All experiments using animals were performed in accordance with the National Institutes of Health Guideline for the Care and Use of Laboratory Animals. Eight-week-old wild-type (WT, C57BL/6 strain) and HDC-KO male mice weighing 22-30 g were used [16]. == Experimental Terutroban design == After administered with sodium pentobarbital (60 mg/kg) for anesthesia, the right common carotid artery was isolated from the surrounding vagus nerve and double-ligated with 6-0 silk sutures to perform rUCCAO. Sham-operated mice were subjected to the same procedure, except for carotid ligation. Terutroban Carnosine and histidine (Sigma, USA) were dissolved in sterile saline and administered by intraperitoneal injection. Adult male.