Blood - nerve barrier characteristics of research

     【Abstract】 The blood-ocular barrier with blood - aqueous

    barrier, the blood - retinal barrier, these special structure on the prevention of eye injury in the process of inflammation

    and immunity play an important role in the occurrence. To date, the blood - nerve barrier (blood-optic nerve barrier)

    the concept of domestic and foreign textbooks, almost no description, this article on the blood - nerve barrier

    characteristics of the study were reviewed.

     Key words blood - nerve barrier of blood - the blood-ocular

    barrier - brain barrier

     Research development of blood-optic nerve barrier

    characteristics

     * KEYWORDS: blood-optic nerve barrier, blood-ocular

    barrier, blood-brain barrier

     0 Introduction

     The eye is an organ immune privilege, there are several factors to maintain the special nature of the eye structure and function play a role, the most important is the blood-

    ocular barrier [1]. It can be useful for selective blood

    filtration material, in order to maintain a stable environment within the eye. When the barriers are harmful factors can affect its function during invasion, resulting in metabolic disorders, resulting in the occurrence of eye disease. Currently accepted blood-ocular barrier with blood - aqueous

    barrier, the blood - retinal barrier, these special structures on the prevention of eye injury in the process of inflammation and immunity play an important role in the occurrence. But so

far, right blood - nerve barrier (blood-optic nerve barrier)

    was highly controversial. Domestic and foreign textbooks, yet the concept. This article on the blood - nerve barrier

    characteristics of the study were reviewed.

     One blood - nerve barrier properties

     1963, Rodriquez-peralta [2] with 2-amino acridine dye

    injection method to observe the blood - nerve barrier

    characteristics of the situation. It was found that intravenous injection of 2-Amino-acridine appears in the optic

    nerve dura mater, but in the subarachnoid space and

    cerebrospinal fluid does not appear; in dural blood vessels, while in the soft meninges and blood vessels within the optic nerve does not appear; in choroid, sclera , Kuhnt tissue appears in the optic nerve did not appear. That the blood

    between the blood and optic nerve - optic nerve barrier

    properties. Barrier structure may be based on the optic nerve and pia mater capillary endothelial cells and their tight junctions.

     Two characteristics of the optic nerve

     Incoming visual information hub of the optic nerve is the only way is to treat the road from the optic nerve to the optic chiasm section. By retinal ganglion cells sent axons fiber drops, the histology of optic nerve and brain parenchyma in the white matter or spinal cord similar to the white

    matter. After the sieve surface, there is no Schwann optic nerve membrane, but there is myelin sheath. The optic nerve in the embryonic development of brain sticking out between the time of the formation of part of the course, as the device.

    There are 3 layers of optic nerve sheath, respectively, with the three-phase continuous layer of meninges. Inner layer of pia mater, the middle of the arachnoid, outer layer of dura mater. Optic nerve mainly consists of 4 above. (1) of the ball

    within a paragraph. (2) orbit segment. (3) The tube segment. (4), intracranial segment. The paragraphs blood supply is extremely complex. Sieve plate anterior optic nerve fibers without myelin sheath, and retinal nerve fibers within the same transparent, and therefore smaller; the sieve plate and sieve plate area after the myelin sheath surrounding the optic nerve fibers there and therefore I increase the thicker in diameter. Therefore, the optic nerve is not an ordinary

peripheral nerve, but central nervous ahead of a prominent

    nerve bundle.

     3 on the blood - nerve barrier properties of the

    controversy

     Since the Rodriquez-peralta in 1963 pairs of blood - to

    explore the characteristics of the optic nerve barrier since the domestic and foreign scholars of the in-depth study. In

    1970 Machemer [3] with alkaline rhodamine B labeled protein, intravenous injection, observed in the optic nerve and surrounding connective tissue are stained intervals, while the optic nerve did not stain. That there exists between the blood

    and optic nerve barrier properties. 1972, Peyman and Apple [4] with the electron microscope the distribution of horseradish peroxidase tracer was observed that there is no tracer into the optic nerve from the optic nerve capillary gap cavity.

    They believe in the existence of blood-brain barrier

    characteristics of the optic nerve. But their experiments did not mention whether the observed optic nerve head situation. Domestic scholars Yang Cun et al [5] that the blood vessels of the optic nerve with all the features of the central nervous system, blood vessels and performance of all of the peripheral capillary wall cells and surrounding cells, there is no gap between the endothelial cells and closely connected to the optic nerve microvascular bed is anatomically similar to the retina and central nervous system, blood vessels, and has self-regulation of physiological characteristics and blood-

    brain barrier performance. Made with the blood vessels within the optic nerve - optic nerve barrier performance. The barrier

    and the blood-brain barrier are very similar. The

    choriocapillaris around the optic nerve head does not have this barrier function, allowing free passage of blood substances big pore wall. 1975, Grayson and laties [6] After intravenous administration of fluorescein sodium, fluorescent material was observed around the optic nerve to the optic nerve from the spread. That the optic nerve and the lack of a close connection between the choroid from a structural point of view is not a complete barrier to keep only the physical barrier function. 2001, Hofman et al [7] the use of advanced blood-brain barrier, non-blood-brain barrier-specific marker

    of vascular permeability markers, combined with electron microscopy, pairs of optic nerve microvascular research. Found

    that the former area of optic nerve head capillaries lack of

blood-brain barrier properties, a weak blood-brain barrier-

    specific marker expression or no expression, endothelial cells were connected fenestrae-like cracks that contain many

    pinocytotic vesicles on the part of the plasma proteins with a transparent sex. The sieve plate area, sieve with a blood-

    brain barrier characteristics of the zone of capillary. Strong positive blood-brain barrier-specific marker expression,

    endothelial cell fenestrae-like and were not linked with fewer pinocytotic vesicles. Domestic scholars Amy [8] that the optic nerve head blood supply from the two systems, from the central retinal artery is a non-permeability of blood vessels

    associated with the choriocapillaris part of a certain

    material can be dispersed. Therefore, the blood - nerve

    barrier may belong to the blood - brain barrier part of the

    defect.

     4 blood - nerve barrier properties of research prospects

     Based on the current findings, the general view that does exist between the blood and the blood in the optic nerve -

    optic nerve barrier properties. Textbooks at home and abroad have not yet see the blood - the concept of the optic nerve

    barrier. Barrier structure may be based on the optic nerve and

    pia mater capillary endothelial cells and their tight junctions. Selective adoption of useful substances in the blood to maintain a relatively stable environment within the optic nerve. As for some of the small molecular weight tracer

    extravasation, in order to sieve the former area of blood -

    nerve barrier endothelial cell tight junctions between the bite was small with a small fracture sample, pinocytotic vesicles are more than just blood-brain barrier permeability

    increased due. However, for larger molecules with a barrier.

     "Immune privilege (Immune privilege)" The concept was first originated from the 19th century 70's, at that time, Doorremal found in the rabbit anterior chamber in certain human tumor cells can survive. The 20th century, 40 years,

    Medawar was found planted in the anterior chamber of the graft can survive a long time. Later, people are increasingly recognized as the eye is an organ immune privilege claim. Eye immune privilege is involved and the maintenance of a variety

    of factors, the most important thing is the blood-ocular

    barrier, its meaning is to maintain the integrity of the organization to prevent the occurrence of autoimmune

inflammatory processes. Blood - the barrier characteristics of

    the optic nerve blood-ocular barrier, as an important part of the same limiting effect of blood-borne immune cells and

    molecules into the character. Compared with other parts of the blood vessels in normal physiological conditions, the dominant optic nerve complex vascular network has significant

    restrictions on blood-borne cells and molecules into the eye of the characteristics of the organization. Thus, to some extent the immune response blocked outgoing access. Blood -

    the optic nerve barrier characteristics of severely

    restricting the blood-borne cells and molecules into the eye, while the blood flow in the immune effectors, including the sensitized T cells and antibodies were also largely outside of this barrier to the optic nerve.

     Therefore, the blood - nerve barrier feature is the eyes,

    one of the most important defense mechanism, its special defense capability and its associated mechanisms for the prevention and reduction of optic nerve inflammation, reducing trauma, inflammation, hypoxia and other damage of great

    significance. In addition, the blood - nerve barrier

    properties are still ophthalmic drug research that has practical value, although the eye there are many Chinese and Western medicine has been used clinically for many years, but these drugs in the effective concentration of the optic nerve is not easy detection, if the right blood - nerve barrier

    Features an open and transparent mechanism for in-depth study

    will provide clinical ophthalmology drug development and improve the treatment of optic nerve injury provide important

    theoretical basis and experimental data. Therefore, the blood - nerve barrier properties to explore important. Reposted elsewhere in the paper for free download http://

     The current response of blood - nerve barrier properties

    of a deeper, more detailed, more comprehensive study. Such as observations What other unknown structures involved in the blood - nerve barrier function of the composition, which features induced adjustment factors. Optic neuropathy in order to deepen understanding of the mechanisms for the prevention and treatment of optic nerve lesions provide theoretical support.

     5 affect the blood - nerve barrier factors

     The researchers found that despite the eye of the environment is relatively very stable, but the blood-ocular

    barrier by many factors, they can make the material through the blood-ocular barrier in the apparent rate of change. Similarly, the blood - nerve barrier properties as a blood-

    ocular barrier is often an integral part of the subject to a

    number of factors.

     5.1 Blood - inflammation of the optic nerve barrier

    properties and the present study shows that, resulting in blood - nerve barrier characteristics of the main factors is the inflammatory destruction of optic nerve injury [9]. The

    study found that when malaria infection, optic neuropathy occurred in mice at the same time, along with the optic nerve axon and myelin sheath structure, such as nerve damage, glial cell morphology and distribution of abnormal mononuclear cells in the vascular endothelial proliferation. Description of these inflammatory changes and blood - nerve barrier

    characteristics are intrinsic relevance. Moreover, the study also found that the blood - the optic nerve barrier

    characteristics of neurological damage in mice before clinical

    symptoms have occurred, indicating the optic nerve of vascular endothelial injury and brain injury has not synchronized, suggesting that the blood - the optic nerve than in the blood-

    brain barrier properties barrier more easily destroyed as a

    result of the inflammatory response [10].

     5.2 Blood - nerve barrier properties and mechanical

    trauma, or trauma can also cause blood pressure - the

    destruction of the optic nerve barrier properties. The study found optic nerve trauma, and even the optic chiasm tumor

    suppression, can result in blood - nerve barrier function

    damage. Possible reason is that the injury has directly undermined the structure of the optic nerve, vascular endothelial damage, leading to blood - nerve barrier of the

    direct damage, while chronic tumor growth, a longer period of oppression, invasion and secretion of inflammatory injury factor to the optic nerve occurs edema, further exacerbating the optic nerve and vascular endothelial damage, secondary cause of blood - the destruction of the optic nerve barrier [11], thus becoming the destructive effects of indirect optic nerve injury.

     5.3 Blood - nerve barrier properties and MMP recent

    studies [12] The metalloproteinases (matrixmetalloproteases, MMP) and blood - the relationship between the optic nerve barrier properties have been studied and found that when the blood - nerve barrier function destroyed, MMP-9 expression was

    significantly lower that the MMP-9 and the maintenance of

    blood - is closely related to the integrity of the optic nerve barrier. To prevent the use of MMP agent study further confirmed this point and found that application of MMP to prevent fluid MMP-1, -2, and -9 increased levels of TIMP-1 and

    TIMP-2 levels decreased, thereby to improve the optic nerve

    injury, blood - the optic nerve barrier properties to be protected [13].

     5.4 Blood - nerve barrier properties and clinical drug hypertonic dehydration agents are commonly used IOP-lowering

    drugs, a series of studies have shown that: A number of

    intraocular pressure lowering drugs, as well as aldose reductase, sorbitol dehydrogenase, histamine, adenosine, substances such as anti-cholinesterase drugs have similar

    effect. Can make the eye increased the concentration of other drugs, further research found that they can cause blood-ocular

    barrier open. Similarly, hypoxia, inflammation of the state, can lead to blood - nerve barrier properties destroyed,

    permeability increase. The study found that the inflammatory state, the optic nerve vascular endothelial permeability

    increase, barriers will increase the pass rate of drugs [14].

     【References】

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     2 Rodriguez-Peralta, LA. The blood-optic nerve barrier. Anat

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     3 Machemer R. Angiographic-histologic correlation of eye

    vessel permeability with protein bound fluorescent dye. Am J Ophthalmol, 1970; 69:27-38

     4 Peyman GA, Apple D. Peroxidase diffusion processes in the optic nerve. Arch Ophthalmol, 1972; 88:650-654

     5 Yang Cun, Cao Mu-Rong, PENG Guang-Hua. Optic neuropathy.

    1st edition. Zhengzhou: Henan Science and Technology Publishing House, 1996:5

     6 Grayson MC, Laties AM. Ocular localization of sodium fluorescent: Effects of administration in rabbit and monkey. Arch Ophthalmol, 1971; 85:600-609

     7 Hofman P, Hoyng P, vanderWerf F, Vrensen GF, Schlingemann RO. Lack of Blood-Brain Barrier properties in microvessels of the prelaminar optic nerve head. Invest Ophthalmol Vis Sci, 2001; 42 (5) :895-901

     8 Amy. Ophthalmology book. 1st edition. Beijing: People's

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     9 Pena JD, Agapova O, Gabelt BT, Levin LA, Lucarelli MJ, Kaufman PL, Hernandez MR. Increased Elastin Expression in Astrocytes of the Lamina Cribrosa in Response to Elevated Intraocular Pressure. Invest Ophthalmol Vis Sci, 2001;

    42:2303-2314

     10 Ma N, Madigan MC, Chan-Ling T, Hunt NH. Compromised blood-

    nerve barrier, astrogliosis, and myelin disruption in optic nerves during fatal murine cerebral malaria. Glia, 1997; 19 (2) :135-151

     11 Levin LA, Gragoudas ES, Lessell S. Endothelial cell loss in irradiated optic nerves. Ophthalmology, 2000; 107 (2) :370-

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     12 Ahmed Z, Dent RG, Leadbeater WE, Smith C, Berry M, Logan A. Matrix metalloproteases: degradation of the inhibitory environment of the transected optic nerve and the scar by regenerating axons. Mol Cell Neurosci, 2005; 28 (1): 64-78

     13 Hughes PM, Wells GM, Perry VH, Brown MC, Miller KM. Comparison of matrix metalloproteinase expression during Wallerian degeneration in the central and peripheral nervous systems. Neuroscience, 2002; 113 (2) :273-287

     14 Kiernan JA. Axonal and vascular changes following injury

    to the rat's optic nerve. J Anat, 1985; 141:139-154 reposted

    elsewhere in the paper for free download http://