AIM: To explore the expression of insulin-like growth factor-1(IGF-1)in extraocular muscle and serum of children with normal eye position and strabismus, in order to further understand the correlation between pathogenesis of strabismus and IGF-1.

METHODS: Children were divided into 3 groups according to the position of eye and the type of strabismus as follow: concomitant esotropia group(67 cases), concomitant exotropia group(129 cases)and normal eye position group(23 cases). For each group of the children, the extraocular muscle were cut out and frozen for detecting the expression pattern of IGF-1 by means of immunohistochemistry and Western-blot. We also used ELISA to measure the serum level of IGF-1.

RESULTS:(1)Result detected by immunohistochemistry: IGF-1 was expressed mainly in the cytoplasm of extraocular muscle cells, small amount of IGF-1 was expressed in the extracellular matrix. The expression of IGF-1 in extraocular muscle of normal eye position group was significantly more than that of concomitant esotropia group and concomitant exotropia group(P<0.05).(2)Result detected by Western blot: compared with concomitant esotropia group and concomitant exotropia group,the expression of IGF-1 in normal eye position group was significantly increased(P<0.05).(3)The difference of serum level of IGF-1 among normal eye position group, concomitant esotropia group and concomitant exotropia group was not statistically significant(P>0.05).

CONCLUSION: The occurrence of simple abnormal eye position such as concomitant esotropia and concomitant exotropia in children may has few association with the level of IGF-1 in serum, but be associated with the expression of IGF-1 in extraocular muscle. It suggests that injecting IGF-1 into extraocular muscle may be a potiential application for curing strabismus.