| The central nervous system (CNS) has traditionally been regarded as an immunologically privileged organ. This view has been based on four main arguments including the lack of lymphatic draining, the presence of a tight blood-brain barrier ( BBB ), the impaired rejection of transplants, and the low level expression of major histocompatibility complex ( MHC ) and adhesion molecules. However, accumulating evidence suggests that the concept of immunological privilege within the CNS needs reevaluation. The CNS as an immunocompetent organ has received increasing attention. Recent evidence that microglia, astrocytes and mast cells secrete numerous cytokines, it is widely accepted that these cells participate actively in an integrative communication between resident immune cells of the CNS and those of the periphery. The CNS can tum on, restrict and regulate the immune system. These communications between cells of the immune and nervous systems occur via the coordinated use of surface structures (MHC class II, costimulatory and adhesion molecules, as well as receptors ) and soluble mediators (hormones, cytokines, neurotrophic factors and synaptic transmitters). In acute multiple sclerosis (MS) or experimental allergic encephalomyelitis (EAE) models, early disruption in the integrity of the BBB precedes brain infiltration by infammatory cells or any clinical evidence of disease. BBB permeability could be affected by vasoactive mediators and cytokines released from perivascular brain mast cells, microglia and astrocytes. Although immune and inflammatory response of CNS hasnever been reported in animal asthma model, it is possible that the response can be produced in monkey and rat anaphylaxis shock model.With recent evidence that both microglia and astrocytes secrete numerous cytokines, it is widely accepted that these cells participate actively in an integrative communication between resident immune cells of the CNS and those of the periphery. With the research development to asthma, it has find there is tight relationship between CNS and that of periphery, when challenged with antigen, the brain of sensitized animal manifest neuroplasticity in some nucleus. Morphologic changes in the paraventricular nucleus (PVN) of the hypothalamus, in hypophyseal frontal lobe and adrenal cortex are adaptive and reactive changes. In status asthmaticus, there is a high hormonal activity manifesting morphologically with hypertrophic neurosecretory granules. The Thl/Th2 paradigm in CNS is imbalance toward to Th2 direction. All these findings indicate that asthma is not a "Free-standing event" of "independent organ" in periphery, multiple mechanism including CNS take part in the pathophysiological changes of asthma.Top down central nervous system (CNS) influences on the immune system and bottom up immune system in fluences on the CNS take part in a complex feedforward and feedback loop which may be responsible for initiating events and perpetuating circumstances in the course of neuropsychiatric as well as immune system diseases. The interplay between neurologic and immune systems may help to uncover the pathophysiologies of certain neuropsychiatric systems. This may provide new strategies for pharmacologic anti-inflammatory treatments.It h as b een k nown for so me t hat b rain i s e ndowed w ith a n e nzyme s ystem (the so-called 5-LO pathway) for the synthesis of LTs. All LTs, whether biologically active or not, are removed from brain through a transport system located in the blood-brain barrier, which keeps the balance of LTs level in CNS. The changes of LTs level and 5-LO pathway has correlative connect in many diseases, but to date there still no report about their effect in brain on asthma function. To explore if LTs also have correlative change between CNS and lung tissue in asthma rat, which help to understand the mechanism of asthma, we take these study.Antigen ovalbumin was administrated by sc injection to sensitized male SD rats,after challenged by exposure to an aerosol of ovalbumin 10 g/L in sali...
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