Constancy Strabismus Weak Side Eye Muscle Morphology Changes And Myod, Pax7 Expression Studies

Objective:to observed the expression of MyoD and Pax7 in constant exotropia, research the role of MyoD and Pax7 in the morphological changes of constant exotropia.Methods:to collect 24 cases with constant exotropia from December 2009 to September 2010 in Affiliated Hospital of Medical College of Qingdao University and then divide them into 3 groups which are the group of children with constant exotropia, the group of adults with constant exotropia and adults control group. Medial rectus muscles were obtained from patients undergoing surgical resection and control muscles were obtained from cornea transport donor. Cross sections were obtained and stained by HE method for observing the pathological changes and measuring the number of myofibers and cross—sectional area of Myofibers, and the average optical desity of MyoD and Pax7.Results:The medial rectus muscles from the patients with extropia showed the remarkable pathological changes. The number of myofibers of adults exotropia (18.77±2.91couple),the sectional area of myofibers (261.76±35.68μm2), the average optical desity of MyoD(0.011±0.006),and the Pax7 (0.013±0.005) comparing with control group (32.53±4.75couple,708,9±62.9μm2,0,028±0.0008,0.027±0.002) obviously decreased(P<0.01). The number of myofibers of children exotropia (20.81±4.27couple), the sectional area of myofibers (282.46±25.22μm2), the average optical desity of MyoD(0.021±0.024),and the Pax7 (0.014±0.004) comparing with adults group,there was no significant difference(P> 0.05).Conclusion:The medial rectus muscles from the patients with extropia showed the pathological changes, mainly with decreased and the atrophy of myofibers. And this may be related with the decreased expression of MyoD and Pax7.