Effects of an anti-transforming growth factor-β agent (pirfenidone) on strabismus surgery in rabbits

Purpose: To evaluate the usefulness of an anti-transforming growth factor-β (TGF-β) agent, pirfenidone (PFD) on postoperative inflammation and fibrosis following strabismus surgery in rabbits. Methods: Both eyes of 16 New Zealand white rabbits underwent reinsertion of the superior rectus muscle (SRM). After reinsertion of the SRM, PFD-loaded liposomes (0.5 mg/ml) were injected into the right eye (PFD group) and normal saline-loaded liposomes was injected into the left eye (control group), subconjunctivally (0.4 ml). To assess the postoperative inflammatory changes and fibrosis of the SRM, immunofluorescence staining with anti-CD11b antibody was performed at 3 days postoperatively, and Masson's trichrome staining was performed at 4 weeks postoperatively. To evaluate the toxicity of PFD on muscle fibers, the integrity of the muscle fibers was examined by transmission electron microscopy (TEM) at 3 days and 4 weeks postoperatively. Results: CD11b protein expression was significantly reduced in the PFD group compared with the control group at 3 days postoperatively (p = 0.012). Masson trichrome staining, which stains collagen, was diminished in the PFD group at 4 weeks postoperatively. TEM revealed disorganized muscle fibers and vacuoles in both groups, but this was less prominent in the PFD group. Conclusions: Intraoperative injection of PFD may be effective as an adjunctive treatment to decrease inflammation and fibrosis resulting from strabismus surgery.