Abstract
Purpose: :
To investigate whether cervical sympathectomy (iatrogenic Horner's syndrome) induces the morphological changes of extraocular muscles and orbital fat in rats.
Methods: :
Unilateral cervical ganglionectomy was done on Sprague-Dawley rats (n=9). Sympathetic innervation to the eye was destroyed by surgical removal of the right superior cervical ganglion (superior cervical ganglionectomy; SCGx). The signs of iatrogenic Horner's syndrome in these rats included right ptosis and enophthalmos. After 8 weeks, we extracted bilateral extraocular muscles and orbital fat from rats. The changes of each tissue were observed and compared using both light and electron microscopy.
Results: :
After cervical ganglionectomy, there were no morphological changes between the control (left) and the experimental (right) orbital fat tissue in rats. However, the right extraocular muscle (EOM) fibers showed a smaller diameter than the left under light microscopy. We observed that the number and size of mitochondria were decreased in the right EOM tissue compared to the left using electron microscopy.
Conclusions: :
EOM fiber diameter, number, and size of the mitochondria were significantly attenuated after cervical ganglionectomy in rats. Our data suggest that extraocular muscle atrophy and changes of mitochondria in EOM may take part in understanding enophthalmos after cervical sympathectomy.
Keywords: anatomy • extraocular muscles: structure • pathology: experimental