The histopathological and functional change of levator palpebrae superioris and müller's muscle in rabbit after subconjunctival injection of triamcinolone acetonide

1. Minwook Chang
2. Sehyun Baek

Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea

Purpose: To evaluate The histopathological and functional change of levator palpebrae superioris and müller's muscle in rabbit after subconjunctival injection of triamcinolone acetonide.

Methods: 24 white New-zealand rabbits were divided into placebo and treated group and given 0.5 and 1.0 cc triamcinolone acetonide injection into the subconjunctival area to the right eyes each, and normal saline injection to the left eyes. Follow up was done at 1,2,4 and 6 weeks and evaluate the histopathological change of levator and müller's muscle, changes of mean transectional area of the müller's muscle , changes of upper lid height (MRD1), and changes of contractility of müller's muscle using western blot method. And we also compared these 2 treated groups according to the amount of injection.

Results: No specific changes of upper lid height were noted in both treated and placebo groups. There were no significant histopathological changes found in levator muscles. However, significant atrophy and thinning of müller's muscles were found at the early follow up periods and these changes were reversible and influenced by the amount of injection.

Conclusions: Subconjunctival injection of triamcinolone acetonide at the upper eyelids appears to influence both the histopathological and functional change of müller's muscles temporally. It might explain the effect of improvement of lid retraction in thyroid related orbitopathy. regardless of no specific change in levator muscle.