{"id":81120,"date":"2016-06-07T01:50:21","date_gmt":"2016-06-07T01:50:21","guid":{"rendered":"http:\/\/healthmedicinet.com\/i\/pathological-findings-in-a-dachshund-cross-dog-with-neuroaxonal-dystrophy\/"},"modified":"2016-06-07T01:50:21","modified_gmt":"2016-06-07T01:50:21","slug":"pathological-findings-in-a-dachshund-cross-dog-with-neuroaxonal-dystrophy","status":"publish","type":"post","link":"http:\/\/healthmedicinet.com\/i\/pathological-findings-in-a-dachshund-cross-dog-with-neuroaxonal-dystrophy\/","title":{"rendered":"Pathological findings in a Dachshund-cross dog with neuroaxonal dystrophy"},"content":{"rendered":"

Two Dachshund-cross breed puppies belonging to the same litter developed progressive
\n difficult walking since they were a few weeks old. One puppy was euthanized without
\n post mortem examination, while the other puppy was presented at 1\u00a0year of age for
\n clinical examination. Neurological examination reveled hypermetria, proprioceptive
\n positioning deficits and irreversible ataxia, particularly of the hind limbs. Muscular
\n tone, bulk and strength were normal and higher mental functions appeared integral.
\n The dog was humanely euthanatized because of the progressive incurable nature of the
\n disease.\n <\/p>\n

At necropsy, brain, spinal cord, tracts of the sciatic nerve, as well as samples from
\n a number of forelimb muscles, liver, and kidney were collected and promptly fixed
\n in 10\u00a0% neutral buffered formalin. Coronal sections were obtained at six different
\n levels of the encephalon (basal nuclei, thalamus, mesencephalon, pons, medulla oblongata,
\n cerebellum), as well as at the levels of each emergence of the nerves of the spinal
\n cord and then routinely processed and embedded in paraffin wax. Sections were cut
\n serially from paraffin blocks at 5\u00a0\u00b5m and stained using hematoxylin and eosin, modified
\n Period Acid Shiff Picro Indigocarmine Morel\u2013Maronger (PAS-M.M.), Kl\u00fcver-Barrera Luxol
\n fast Blue (KB), and Perl\u2019s stain. Furthermore, in-depth immunohistochemical investigations
\n were performed on selected tissue sections using specific primary antibodies for the
\n following markers of axonal transport: neurofilaments light chain (NF-Ls,) and tau,
\n cytoskeletal proteins; ubiquitin, a heat shock protein; synaptophysin, a synapse-associated
\n protein; glial fibrillary acidic protein (GFAP), the specific marker of astrocytes
\n (Table\u00a01<\/a>). To investigate the possible role of autophagic mechanisms in the formation of spheroids,
\n a specific primary antibody against the autophagosomal microtubule associated protein
\n 1A\/1B-light chain 3 B (LC3B) was used (Table\u00a01<\/a>). Primary antibodies were always incubated overnight at 4\u00a0\u00b0C and immunoreactivity
\n (IR) was detected via the biotin-avidin-peroxidase method, using the 3,3?-diaminobenzidine
\n as a chromogen, Additional technical details are shown in Table\u00a01<\/a>. Transversal and longitudinal sections of the sciatic nerve as well as sections from
\n muscles, liver and kidney were also embedded in paraffin, cut serially from the paraffin
\n blocks at 5\u00a0?m and stained using hematoxylin and eosin. Finally, sections of the sciatic
\n nerve were also stained immunohistochemically for GFAP, and histochemically for myelin
\n by using KB technique. Immunohistochemically negative controls were obtained by omitting
\n the primary antibody and using normal brain tissues of two crossbreed dogs aged 6\u00a0months
\n and 1\u00a0year, respectively.<\/p>\n

Table\u00a01.<\/strong><\/a> Technical details of the immunohistochemical examinations\n <\/p>\n

At necroscopy, no gross changes were observed. Histological examination throughout
\n the central nervous system (CNS) revealed a bilateral symmetric neuroaxonal dystrophy,
\n which was uniquely at the level of the ventral posterior lateral nucleus of the thalamus,
\n medial lemniscus, gracilis nucleus, and medial cuneatus nucleus in the brain. The
\n same change in the spinal cord was found in the gracilis and cuneatus fasciculi, particularly
\n in the thoracic tract (Fig.\u00a01<\/a>). In the transversal sections, neuroaxonal changes were characterized by 3\u201350\u00a0\u00b5m
\n sized axonal spheroids, round to ovoid in shape and stained slight to intensely eosinophilic
\n (Fig.\u00a02<\/a>a).<\/p>\n

\"thumbnail\"Fig.\u00a01.<\/strong><\/a> Distribution of the axonal spheroids. Illustration of the encephalic and spinal sections
\n indicating the fasciculi and nuclei with spheroids throughout the central nervous
\n system. Brain section: Red dotted circle<\/em>: ventral posterior lateral nucleus of the thalamus; yellow dotted circle<\/em>: medial lemniscus; turquoise dotted circle<\/em>: gracilis nucleus; blue dotted circle<\/em>: medial cuneatus nucleus. Spinal cord sections: turquoise dotted circle<\/em>: funiculis gracilis; blue dotted circle<\/em>: funiculis cuneatus\n <\/p>\n

\"thumbnail\"Fig.\u00a02.<\/strong><\/a> Photomicrographs of the histological patterns. Section of the medulla oblongata showing
\n the medial cuneatus nuclei (a<\/strong>). Presence of numerous 3\u201350\u00a0\u00b5m sized eosinophilic axonal spheroids (arrow head<\/em>), some of them are vacuolized (arrow<\/em>). Thoracic tract the spinal cord (b<\/strong>). Longitudinal section at level of gracilis and cuneatus fasciculi displays digestion
\n chambers with axonal debris and scattered macrophages (asterisk<\/em>). HE. Bar<\/em>\u00a0=\u00a0100\u00a0\u00b5m\n <\/p>\n

In longitudinal sections at the level of the gracilis and cuneatus fasciculi, aspects
\n of Wallerian-like degeneration with different digestion chambers containing sporadic
\n macrophage and axonal debris were found (Fig.\u00a02<\/a>b). Occasionally, spheroids were found in the dorsal horn of the spinal cord.\n <\/p>\n

Histochemical staining revealed that some spheroids contained PAS-M.M positive material
\n and KB staining evidenced relative preserved myelin. Perl\u2019s stain did not highlight
\n the presence of iron in any sections of the encephalon.\n <\/p>\n

In all CNS sections, spheroids showed immunoreactivity for NF-Ls, tau, synaptophysin
\n and ubiquitin with the signal being more intense at the level of the spinal cord (Fig.\u00a03<\/a>). In addition, immunohistochemistry for LC3B protein detected an intense autophagosome
\n accumulation within spheroids (Fig.\u00a03<\/a>).<\/p>\n

\"thumbnail\"Fig.\u00a03.<\/strong><\/a> Photomicrographs showing immunohistochemical reactivity of axonal spheroids. Transversal
\n sections of thoracic spinal cord (gracilis and cuneatus fasciculi) show numerous spheroid
\n immunohistochemically reactive (IR) for neurofilaments (a<\/strong>), tau (c<\/strong>), synaptophysin (e<\/strong>), ubiquitin (g<\/strong>), and LC3B (i<\/strong>) of thoracic tract of the spinal cord the NAD-affected puppy. As expected, single
\n spheroids were identified in the healthy dog (b<\/strong>, d<\/strong>arrow head<\/em>), while LC3B IR is observed in the glial cells of the affected and control dogs (i<\/strong>, j<\/strong>). Synapthophysin was also evident in the neuropil of the control (f<\/strong>). Avidin\u2013biotin-peroxidase complex method with Mayer\u2019s hematoxylin counterstain.
\n Bar<\/em>\u00a0=\u00a0100\u00a0\u00b5m\n <\/p>\n

Finally, the immunohistochemistry for GFAP confirmed the presence of evident astrogliosis
\n and astrocytosis in the nuclei displaying spheroids. The sections from muscles, liver,
\n kidney and sciatic nerve were histologically normal. As in the control, the affected
\n dog showed weak GFAP immunoreactivity with a linear pattern in the longitudinal sections
\n of the sciatic nerve (Fig.\u00a04<\/a>). In the same nerve, no demyelization was observed by using KB stain.<\/p>\n

\"thumbnail\"Fig.\u00a04.<\/strong><\/a> Photomicrographs of the immunohistochemical reactivity of the sciatic nerve. Sciatic
\n nerve from NAD-affected dog (a<\/strong>) and healthy control dog (b<\/strong>). Longitudinal section of sciatic nerve shows weak linear immunohistochemical reactivity
\n for GFAP both in affected (a<\/strong>) and healthy dog (b<\/strong>). Avidin\u2013biotin-peroxidase complex method with Mayer\u2019s hematoxylin counterstain.
\n Bar<\/em>\u00a0=\u00a0100\u00a0\u00b5m\n <\/p>\n

On the basis of these clinical, histopathological and immunohistochemical features,
\n a NAD disorder was diagnosed.\n <\/p>\n","protected":false},"excerpt":{"rendered":"

Two Dachshund-cross breed puppies belonging to the same litter developed progressive difficult walking since they were a few weeks old. One puppy was euthanized without post mortem examination, while the other puppy was presented at 1\u00a0year of age for clinical examination. Neurological examination reveled hypermetria, proprioceptive positioning deficits and irreversible ataxia, particularly of the hind Read More<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-81120","post","type-post","status-publish","format-standard","hentry"],"_links":{"self":[{"href":"http:\/\/healthmedicinet.com\/i\/wp-json\/wp\/v2\/posts\/81120","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/healthmedicinet.com\/i\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/healthmedicinet.com\/i\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/healthmedicinet.com\/i\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/healthmedicinet.com\/i\/wp-json\/wp\/v2\/comments?post=81120"}],"version-history":[{"count":0,"href":"http:\/\/healthmedicinet.com\/i\/wp-json\/wp\/v2\/posts\/81120\/revisions"}],"wp:attachment":[{"href":"http:\/\/healthmedicinet.com\/i\/wp-json\/wp\/v2\/media?parent=81120"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/healthmedicinet.com\/i\/wp-json\/wp\/v2\/categories?post=81120"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/healthmedicinet.com\/i\/wp-json\/wp\/v2\/tags?post=81120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}