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Distribution pattern of axonal cytoskeleton proteins in the human optic nerve head.

Kang MH, Yu DY - Neural Regen Res (2015)

View Article: PubMed Central - PubMed

Affiliation: Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, WA, Australia; Lions Eye Institute, 2 Verdun Street, Nedlands, WA, Australia.

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It is a progressive optic neuropathy where structural loss of retinal ganglion cell (RGC) axons corresponds with functional visual field defect... Glaucoma is distinguished from other optic neuropathies by its selective loss of RGC axons... Superior and inferior peripheral nerve sectors are found to be most vulnerable to pressure induced injury whereas the inner temporal sector is most resilient (Quigley et al., 1988)... At any one time, approximately 80% of NFH and NFM proteins are phosphorylated (Petzold, 2005)... Previous reports have documented that axons of larger RGCs are found to be more vulnerable to glaucomatous axonal injury which are concentrated in the peripheral optic nerve head (Quigley et el., 1982)... Another finding of this study is that all axonal cytoskeleton proteins are evenly distributed across different sectors in the retrolaminar region of the optic nerve head... The intensity of all axonal cytoskeleton proteins in the retrolaminar region was significantly lower when compared to prelaminar, anterior laminar cribrosa and posterior laminar cribrosa regions... RGC axons are unmyelinated in the anterior portion of the optic nerve head (specifically, prelaminar, anterior laminar and posterior lamina cribrosa regions) and becomes myelinated from the retrolaminar region... The presence of myelin may also explain the relatively uniform distribution of cytoskeleton protein within the retrolaminar region... Lastly, we did not find a significant difference in the concentration of tubulin and MAP protein between the different sectors of the optic nerve head... The uniform distribution of these proteins suggests that, unlike neurofilaments, they are less likely to be influenced by, or modulate, regional metabolic activity in the optic nerve head... In conclusion, this study demonstrates significant differences in the sectoral pattern of NFM, NFH and NFHp distribution in the anterior portion of the optic nerve head, which has not been described before to our knowledge... Previously NFs loss and dephosphorylation of NFs have been demonstrated in animal models of optic nerve injury including a glaucoma model (Kashiwagi et al., 2003; Balaratnasingam et al., 2007; Chidlow et al., 2011)... However, using birefringence and the optical properties of the retina, early change in reflectance of retinal nerve fiber layer preceding axonal loss has been documented (Hwang et al., 2011).

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Laminar regions of the human optic nerve in Van Gieson stain.Longitudinal histological section of the human optic nerve demonstrates the prelaminar, anterior lamina cribrosa (anterior LC), posterior lamina cribrosa (posterior LC) and retrolaminar regions (separated by dotted lines). The prelaminar region is in continuation with retinal layers. Choroid layer is situated adjacent to the anterior LC region. Dense collagen beams that extend from the sclera distinguish the posterior LC region. The absence of dense collagen beams and the relative increase in optic nerve diameter characterises the retrolaminar region. Subarachnoid space (SAS*) between pia and dura mater in retrolaminar region is also labelled. Scale bar: 300 μm.
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Figure 1: Laminar regions of the human optic nerve in Van Gieson stain.Longitudinal histological section of the human optic nerve demonstrates the prelaminar, anterior lamina cribrosa (anterior LC), posterior lamina cribrosa (posterior LC) and retrolaminar regions (separated by dotted lines). The prelaminar region is in continuation with retinal layers. Choroid layer is situated adjacent to the anterior LC region. Dense collagen beams that extend from the sclera distinguish the posterior LC region. The absence of dense collagen beams and the relative increase in optic nerve diameter characterises the retrolaminar region. Subarachnoid space (SAS*) between pia and dura mater in retrolaminar region is also labelled. Scale bar: 300 μm.

Mentions: We examined the distribution of cytoskeleton proteins in different sectors of the cross sectional human optic nerve head (Kang et al., 2014). Nine eyes from 8 donors were used, all of which had no documented history of ocular disease or neurodegenerative conditions (mean age 46.9 ± 3.7 years). Following a careful dissection of the optic nerve with its marked orientation, the optic nerve was cut into 30 μm transverse cryosections, perpendicular to the long axis of the optic nerve. Using previously reported immunohistochemistry protocols, the following 6 cytoskeleton proteins were stained; 1) phosphorylated neurofilament heavy subunit (NFHp), 2) neurofilament heavy subunit (NFH), 3) neurofilament medium subunit (NFM), 4) neurofilament light subunit (NFL), 5) tubulin and 6) microtubule-associated protein (MAP). Each of the antibody labelled proteins were visualised using a confocal scanning laser microscope. Based on previously described histological criteria, we divided the optic nerve head into four specific laminar compartments; prelaminar, anterior lamina cribrosa, posterior lamina cribrosa and retrolaminar regions (Figure 1). Separate images were captured from these four laminar compartments. For quantitative analysis purposes, all optic nerve images were divided into 8 sectors (Figure 2). A quantitative histogram function was used to calculate average pixel intensity per 10 μm2 sample window in each of the 8 sectors. In each sector, total neural area of 7,200 μm2 collected from 72 sample windows was measured. To standardize measurements within each image, the pixel intensity of each sector was expressed as a percentage of the pixel intensity of the inner temporal sector within each image. Standardized stain intensity of cytoskeleton proteins from each sector across four laminar regions of optic nerve head is provided in a separate paper (Kang et al., 2014).


Distribution pattern of axonal cytoskeleton proteins in the human optic nerve head.

Kang MH, Yu DY - Neural Regen Res (2015)

Laminar regions of the human optic nerve in Van Gieson stain.Longitudinal histological section of the human optic nerve demonstrates the prelaminar, anterior lamina cribrosa (anterior LC), posterior lamina cribrosa (posterior LC) and retrolaminar regions (separated by dotted lines). The prelaminar region is in continuation with retinal layers. Choroid layer is situated adjacent to the anterior LC region. Dense collagen beams that extend from the sclera distinguish the posterior LC region. The absence of dense collagen beams and the relative increase in optic nerve diameter characterises the retrolaminar region. Subarachnoid space (SAS*) between pia and dura mater in retrolaminar region is also labelled. Scale bar: 300 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4590219&req=5

Figure 1: Laminar regions of the human optic nerve in Van Gieson stain.Longitudinal histological section of the human optic nerve demonstrates the prelaminar, anterior lamina cribrosa (anterior LC), posterior lamina cribrosa (posterior LC) and retrolaminar regions (separated by dotted lines). The prelaminar region is in continuation with retinal layers. Choroid layer is situated adjacent to the anterior LC region. Dense collagen beams that extend from the sclera distinguish the posterior LC region. The absence of dense collagen beams and the relative increase in optic nerve diameter characterises the retrolaminar region. Subarachnoid space (SAS*) between pia and dura mater in retrolaminar region is also labelled. Scale bar: 300 μm.
Mentions: We examined the distribution of cytoskeleton proteins in different sectors of the cross sectional human optic nerve head (Kang et al., 2014). Nine eyes from 8 donors were used, all of which had no documented history of ocular disease or neurodegenerative conditions (mean age 46.9 ± 3.7 years). Following a careful dissection of the optic nerve with its marked orientation, the optic nerve was cut into 30 μm transverse cryosections, perpendicular to the long axis of the optic nerve. Using previously reported immunohistochemistry protocols, the following 6 cytoskeleton proteins were stained; 1) phosphorylated neurofilament heavy subunit (NFHp), 2) neurofilament heavy subunit (NFH), 3) neurofilament medium subunit (NFM), 4) neurofilament light subunit (NFL), 5) tubulin and 6) microtubule-associated protein (MAP). Each of the antibody labelled proteins were visualised using a confocal scanning laser microscope. Based on previously described histological criteria, we divided the optic nerve head into four specific laminar compartments; prelaminar, anterior lamina cribrosa, posterior lamina cribrosa and retrolaminar regions (Figure 1). Separate images were captured from these four laminar compartments. For quantitative analysis purposes, all optic nerve images were divided into 8 sectors (Figure 2). A quantitative histogram function was used to calculate average pixel intensity per 10 μm2 sample window in each of the 8 sectors. In each sector, total neural area of 7,200 μm2 collected from 72 sample windows was measured. To standardize measurements within each image, the pixel intensity of each sector was expressed as a percentage of the pixel intensity of the inner temporal sector within each image. Standardized stain intensity of cytoskeleton proteins from each sector across four laminar regions of optic nerve head is provided in a separate paper (Kang et al., 2014).

View Article: PubMed Central - PubMed

Affiliation: Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, WA, Australia; Lions Eye Institute, 2 Verdun Street, Nedlands, WA, Australia.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

It is a progressive optic neuropathy where structural loss of retinal ganglion cell (RGC) axons corresponds with functional visual field defect... Glaucoma is distinguished from other optic neuropathies by its selective loss of RGC axons... Superior and inferior peripheral nerve sectors are found to be most vulnerable to pressure induced injury whereas the inner temporal sector is most resilient (Quigley et al., 1988)... At any one time, approximately 80% of NFH and NFM proteins are phosphorylated (Petzold, 2005)... Previous reports have documented that axons of larger RGCs are found to be more vulnerable to glaucomatous axonal injury which are concentrated in the peripheral optic nerve head (Quigley et el., 1982)... Another finding of this study is that all axonal cytoskeleton proteins are evenly distributed across different sectors in the retrolaminar region of the optic nerve head... The intensity of all axonal cytoskeleton proteins in the retrolaminar region was significantly lower when compared to prelaminar, anterior laminar cribrosa and posterior laminar cribrosa regions... RGC axons are unmyelinated in the anterior portion of the optic nerve head (specifically, prelaminar, anterior laminar and posterior lamina cribrosa regions) and becomes myelinated from the retrolaminar region... The presence of myelin may also explain the relatively uniform distribution of cytoskeleton protein within the retrolaminar region... Lastly, we did not find a significant difference in the concentration of tubulin and MAP protein between the different sectors of the optic nerve head... The uniform distribution of these proteins suggests that, unlike neurofilaments, they are less likely to be influenced by, or modulate, regional metabolic activity in the optic nerve head... In conclusion, this study demonstrates significant differences in the sectoral pattern of NFM, NFH and NFHp distribution in the anterior portion of the optic nerve head, which has not been described before to our knowledge... Previously NFs loss and dephosphorylation of NFs have been demonstrated in animal models of optic nerve injury including a glaucoma model (Kashiwagi et al., 2003; Balaratnasingam et al., 2007; Chidlow et al., 2011)... However, using birefringence and the optical properties of the retina, early change in reflectance of retinal nerve fiber layer preceding axonal loss has been documented (Hwang et al., 2011).

No MeSH data available.


Related in: MedlinePlus