Abstract
Purpose: :
Tenascin-C is a member of the Tenascin family of cell adhesion glycoproteins that are present in mesenchyme surrounding fetal mammary glands, hair follicles, and teeth. In the adult it remains present in tendons, myotendinous junctions, pericardium, periosteum, perineurium, and smooth muscle. Its clinical utility is that it is expressed in the stroma of undifferentiated mammary tumors. Ophthalmologically, Tenascin-C has been demonstrated in the limbus region, conjunctiva, Descemet’s membrane, and the tunica interna of blood vessels. In cadaveric specimens, Jaggi et al demonstrated that Tenascin-C was not identified in human extraocular muscle. Immunohistochemcal staining of resected strabismic extraocular muscle using Tenascin-C antibody was performed in this study to determine if extracellular matrix differentiation is present
Methods: :
26 resected extraocular muscle specimens obtained during routine strabismus repair were formalin-fixed, paraffin-embeded and stained immunohistochemically with Tenascin-C antibody. 15 were medial recti, and 11 were lateral recti in repairing esotropia.
Results: :
Of the 15 medial recti specimens, 13 stained focally with Tenascin-C antibody. Of the 11 lateral recti specimens 8 stained focally with Tenascin-C antibody.
Conclusions: :
Although not found in cadaveric extraocular muscles, this study found that Tenascin-C is expressed in the majority of resected strabismic extrocular muscles. Whether the negative finding in the cadaver study is artifactual, or whether extracellular matrix differentiation in strabismic extraocular muscle is a cause or effect of ocular misalignment is yet to be determined.
Keywords: extraocular muscles: structure • differentiation • strabismus