Histopathologic Change Following Injection of Steroid Subconjunctivally in Rabbit: I. Resection or Recession of Superior Rectus

Roh, Young Bae; Sin, Dong Hyo; Lee, Sang Hyup; Oum, Boo Sup

Abstract

The authors observed histologic changes after subconjunctival injection of steroid (triamcinolone acetonide; TA) around the operated superior rectus muscle to investigative the alteration of subconjunctival collagen and muscle fibers in rabbits. The TA was identified in the subconjunctival tissue as an eosinophilic, foamy deposit with infiltration of macrophages phagocytosing TA particles and a few inflammatory cells The deposit was surrounded by compact collagen fibers that formed a pseudocapsule. The collagen fibers and fibroblasts were altered and fibrolytic in appearance within and margin of the drug deposit. While there was only mild degeneration in the muscle and its surrounding connective tissue. And the collagen fibers and fibroblasts at the site distant from the TA deposit were normal. There was no difference in histologic findings between the resected and recessed muscles. From these observations, it would appear that TA has a local fibrolytic effect. The localized fibrolytic effect within and marign of the drug deposit may explain, in part, the fibrolytic action of macrophages, which contained phagocytosed TA.