{"id":1183,"date":"2019-06-21T17:03:23","date_gmt":"2019-06-21T09:03:23","guid":{"rendered":"http:\/\/www.bioactivescreeninglibrary.com\/?p=1183"},"modified":"2022-01-07T10:53:32","modified_gmt":"2022-01-07T02:53:32","slug":"total-white-matter-area-significantly-increased-age-control-cords-injury-assessing-damage-spinal-white-matter","status":"publish","type":"post","link":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/2019\/06\/21\/total-white-matter-area-significantly-increased-age-control-cords-injury-assessing-damage-spinal-white-matter\/","title":{"rendered":"The total white matter area significantly increased with age in control cords injury for assessing damage to spinal white matter"},"content":{"rendered":"

In general it is believed that axon counts provide a superior quantitation of residual white matter than simpler methods such as area measurements. Our findings strongly support this. We have used an un-biased stereology based method to estimate myelinated axon numbers at different spinal levels and times after injury. Previous studies of axon counts have been based on the original line-sampling method of Blight. To our knowledge, we are first to use a stereology-based method to do this kind of analysis. Although it does require some initial testing to establish counting parameters, once these are done, the technique is relatively fast, thus enabling accurate resolution of axonal loss in different tracts. Total axon counts obtained here appear to be similar to those estimated previously for the rat spinal cord using the line-sampling method. This technique could also be used to separately estimate numbers of differently sized axons as well as further discriminate between changes in different spinal tracts. However it should be noted that injuries to the spinal cord often make it very difficult to accurately delineate Chlorhexidine hydrochloride<\/a> tracts due to physical distortions of the cord. In addition, unmyelinated fibres and myelinated axons of very small size are excluded. Axons in the dorsal column mainly originate from dorsal root ganglion cells. Axon numbers in control animals increased over the 10-week period on average by about 38% in the dorsal column of the spinal cord sections studied. This may be due to a combination of an increase in the size of small already myelinated fibres or new fibres being myelinated. Our data showed that after injury, there was a rapid loss of axons in the dorsal column at the centre of the injury site such that by 24 hours only 24% remained. From 1 week and later there seemed to be no further loss of dorsal column axons. The degeneration of the distal part of DC fibres is clear given the asymmetrical loss of fibres above, but not below the injury site in all of the injured animals from 1 week and later. The number of fibres increased in the segment rostral to injury and this is presumably the result of axons entering the cord above the lesion site that were not damaged by the primary injury. Similar to the changes at the injury site, axon numbers were very similar at times between 1 and 10 weeks indicating that the degeneration of the distal part of these fibres is over by 1 week. In the caudal part of the DC, the numbers of axons suggest some progressive loss of fibres close to the injury whereas myelination\/remyelination can occur at some distance from the injury. For DC data we initially estimated axon numbers at mm intervals and this showed that at about 4 mm rostral to injury, the axon counts for the 4 and 10 week groups were all above the 24-hour control group and progressively increased with rostral distance from injury site. This indicates that at least in this tract, at more distal levels rostrally, the normal myelinating Gomisin-D<\/a> processes are not much affected and continue after injury. Fibres in ventrolateral tracts are mixed sensory and motor fibres and originate both below and above the injury site. There was a similar relative increase in the number of myelinated fibres in these tracts as in the DC in control animals over the 10 weeks of the study. The overall relative loss of fibres was, however, less in VLT compared to DC. This can be expected since the impact injury was directly above the DC. In the middle of the injury site about 54% of fibres remained at 24 hours and this was further reduced to 13% at 1 week after injury of aged matched controls. Similar to the DC there was no indication of further loss of fibres beyond one week. The total area of white matter in plastic sections was also measured.<\/p>\n","protected":false},"excerpt":{"rendered":"

In general it is believed that axon counts provide a superior quantitation of residual white matter than simpler methods such as area measurements. Our findings strongly support this. We have used an un-biased stereology based method to estimate myelinated axon numbers at different spinal levels and times after injury. Previous studies of axon counts have … Continue reading “The total white matter area significantly increased with age in control cords injury for assessing damage to spinal white matter”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/posts\/1183"}],"collection":[{"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/comments?post=1183"}],"version-history":[{"count":1,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/posts\/1183\/revisions"}],"predecessor-version":[{"id":1184,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/posts\/1183\/revisions\/1184"}],"wp:attachment":[{"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/media?parent=1183"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/categories?post=1183"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/tags?post=1183"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}