目的：观察伴有下斜肌功能亢进的外斜V征患者下斜肌和内直肌中myogenin活性卫星细胞数量的变化，探讨伴有下斜肌功能亢进的外斜V征的可能发病原因。

方法：将伴有下斜肌功能亢进外斜V征患者6例中切除的下斜肌及内直肌作为斜视组，行myogenin免疫组织化学染色，统计myogenin阳性染色的卫星细胞核数； 角膜移植供体的下斜肌及内直肌(6例)作为对照组。

结果：斜视组和对照组下斜肌中myogenin免疫染色阳性肌卫星细胞数占总细胞数比例分别为(22.7±7.03)%和(4.2±0.75)%，具有统计学差异(P<0.05)。斜视组和对照组内直肌中myogenin免疫染色阳性的肌卫星细胞数分别为(2.2±0.75)%和(4.5±1.05)%，具有统计学差异(P<0.05)。

结论：首次报道伴有下斜肌功能亢进外斜V征患者眼外肌中表达myogenin免疫染色阳性肌卫星细胞的变化。myogenin可能是伴有下斜肌功能亢进外斜V征的致病因素。

AIM: To study the number of myogenin-positive activated satellite cells in the inferior oblique muscles and the medial muscles of V-pattern exotropia with inferior oblique overaction, to further explore the possible etiological factors of V-pattern exotropia with inferior oblique overaction.

METHODS: The inferior oblique muscles and the medial muscles were cut from V-pattern exotropia patients with inferior oblique overaction during strabismus operation treated as the strabismus group. Cross sections were stained immunohistochemically for the presence of activated satellite cells, as identified by myogenin immunoreactivity. The inferior oblique muscles and the medial muscles were obtained from the corneal transplant donors(six eyes of six cases), which treated as the control group.

RESULTS: The frequency of myogenin-positive satellite cells of the inferior oblique muscles was(22.7±7.03)% and(4.2±0.75)% in the strabismus group and the control group. Significant differences existed in the expression of myogenin in two groups(P<0.05). Again, the frequency of myogenin-positive satellite cells of the medial muscles was(2.2±0.75)% and(4.5±1.05)% in the strabismus group and the control group. Significant differences also existed in the expression of myogenin in two groups(P<0.05).

CONCLUSION: It is first report that myogenin-positive satellite cells presents in extraocular muscles of V-pattern exotropia with inferior oblique overaction. The current results suggest that myogenin is one of possible etiological factors of V-pattern exotropia with inferior oblique overaction.