Equine laryngeal hemiplegia part IV. muscle pathology

Cahill, Jennifer I.; Goulden, B.E.

doi:10.1080/00480169.1986.35343

Cited by 43 publications

(55 citation statements)

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“…A minor, hybrid fiber type with histochemical characteristics of both fast and slow fibers was also present (Gunn 1972;Cahill and Goulden 1986b;Duncan et al 1991a;LopezPlana et al 1993;Adreani et al 2006). The present work on apparently normal laryngeal muscles, using MyHCs as markers, revealed that the fast fibers could be subdivided into two distinct types, 2a and 2x, each with a distinct motor protein and hence speed of contraction.…”

Section: Muscle Fiber Types In the Cad And Tra Of Horses In The Normamentioning

confidence: 99%

“…Fiber-type grouping is known to occur commonly in equine laryngeal muscles (Gunn 1972;Cahill and Goulden 1986b). Up to 30% of horses with no laryngoscopic evidence of laryngeal hemiplegia show fiber-type grouping and histological evidence of neurogenic atrophy in those laryngeal muscles innervated by the left recurrent laryngeal nerve.…”

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confidence: 99%

“…Early analysis using myosin ATPase enzyme histochemistry revealed the presence of two basic fiber types, type 1 (slow) and type 2 (fast) fibers (Gunn 1972;Mascarello and Veggetti 1979;Cahill and Goulden 1986b;Duncan et al 1991a;Lopez-Plana et al 1993). Work based on SDS-PAGE suggested that laryngeal muscles affected by equine recurrent laryngeal neuropathy (RLN) expressed only two MyHC isoforms, slow and 2B (Adreani et al 2006).…”

mentioning

confidence: 99%

“…Up to 30% of horses with no laryngoscopic evidence of laryngeal hemiplegia show fiber-type grouping and histological evidence of neurogenic atrophy in those laryngeal muscles innervated by the left recurrent laryngeal nerve. These apparently normal horses with fiber-type grouping are referred to as "subclinical" cases of RLN (Gunn 1972;Duncan et al 1974Duncan et al ,1977Cahill and Goulden 1986b;Lopez-Plana et al 1993).…”

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confidence: 99%

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Immunohistochemical Analysis of Laryngeal Muscles in Normal Horses and Horses With Subclinical Recurrent Laryngeal Neuropathy

Rhee

Steel

Derksen

et al. 2009

J Histochem Cytochem.

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Michigan (FJD,NER)S U M M A R Y We used immunohistochemistry to examine myosin heavy-chain (MyHC)-based fiber-type profiles of the right and left cricoarytenoideus dorsalis (CAD) and arytenoideus transversus (TrA) muscles of six horses without laryngoscopic evidence of recurrent laryngeal neuropathy (RLN). Results showed that CAD and TrA muscles have the same slow, 2a, and 2x fibers as equine limb muscles, but not the faster contracting fibers expressing extraocular and 2B MyHCs found in laryngeal muscles of small mammals. Muscles from three horses showed fiber-type grouping bilaterally in the TrA muscles, but only in the left CAD. Fiber-type grouping suggests that denervation and reinnervation of fibers had occurred, and that these horses had subclinical RLN. There was a virtual elimination of 2x fibers in these muscles, accompanied by a significant increase in the percentage of 2a and slow fibers, and hypertrophy of these fiber types. The results suggest that multiple pathophysiological mechanisms are at work in early RLN, including selective denervation and reinnervation of 2x muscle fibers, corruption of neural impulse traffic that regulates 2x and slow muscle fiber types, and compensatory hypertrophy of remaining fibers. We conclude that horses afflicted with mild RLN are able to remain subclinical by compensatory hypertrophy of surviving muscle fibers. (J Histochem Cytochem 57:787-800, 2009)

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Section: Muscle Fiber Types In the Cad And Tra Of Horses In The Normamentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Immunohistochemical Analysis of Laryngeal Muscles in Normal Horses and Horses With Subclinical Recurrent Laryngeal Neuropathy

Rhee

Steel

Derksen

et al. 2009

J Histochem Cytochem.

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“…Evidence of subclinical disease, including axonopathy of the recurrent laryngeal nerve and neurogenic atrophy of the intrinsic laryngeal musculature, is present in nearly twice as many horses. 2,5,6,9 The clinical effects of RLN and the histologic changes in the affected laryngeal muscles have been well characterized; [15][16][17]25,33 however, little is known about the cellular and molecular level events that occur in the laryngeal muscle of horses affected by RLN.…”

Section: Introductionmentioning

confidence: 99%

Myosin Heavy Chain Composition in Normal and Atrophic Equine Laryngeal Muscle

Adreani

Lehar

et al. 2006

Vet Pathol

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Abstract. The myosin heavy chain (MHC) composition of a given muscle determines the contractile properties and, therefore, the fiber type distribution of the muscle. MHC isoform expression in the laryngeal muscle is modulated by neural input and function, and it represents the cellular level changes that occur with denervation and reinnervation of skeletal muscle. The objective of this study was to evaluate the pattern of MHC isoform expression in laryngeal muscle harvested from normal cadavers and cadavers with naturally occurring left laryngeal hemiplegia secondary to recurrent laryngeal neuropathy. Left and right thyroarytenoideus (TA) and cricoarytenoideus dorsalis (CAD) were obtained from 7 horses affected with left-sided intrinsic laryngeal muscle atrophy and from 2 normal horses. Frozen sections were evaluated histologically for degree of atrophy and fiber type composition. MHC isoform expression was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of muscle protein. Histologic atrophy was seen in all atrophic muscles and some right-sided muscles of 3 affected horses, as well as the left TA of 1 normal horse. Fiber type grouping or loss of type I muscle fibers was observed in the left-sided laryngeal muscles in all but 1 affected horse, as well as in the right muscles of 2 affected horses, and the left TA of 1 normal horse. SDS-PAGE showed 2 bands corresponding to the type I and type IIB myosin isoforms in the CAD and TA of the 2 normal horses. Affected horses demonstrated a trend toward increased expression of the type IIB isoform and decreased expression of the type I isoform in atrophic muscles. This study confirmed the presence of histologic abnormalities in grossly normal equine laryngeal muscle, and it demonstrated an increased expression of type IIB MHC with a concurrent decreased expression of type I MHC in affected muscles. Evaluation of muscle fiber changes at the cellular level under denervated and reinnervated conditions may aid in assessing future strategies for reinnervation or regeneration of atrophic laryngeal muscle.

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Ultrasonography of the Larynx for the Diagnosis of Recurrent Laryngeal Neuropathy

Chalmers¹

2014

Advances in Equine Upper Respiratory Surgery

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Equine laryngeal hemiplegia part IV. muscle pathology

Cited by 43 publications

References 5 publications

Immunohistochemical Analysis of Laryngeal Muscles in Normal Horses and Horses With Subclinical Recurrent Laryngeal Neuropathy

Immunohistochemical Analysis of Laryngeal Muscles in Normal Horses and Horses With Subclinical Recurrent Laryngeal Neuropathy

Myosin Heavy Chain Composition in Normal and Atrophic Equine Laryngeal Muscle

Ultrasonography of the Larynx for the Diagnosis of Recurrent Laryngeal Neuropathy

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