Nano-structured, anti-inflammatory sutures improve wound closure and healing in a rabbit model of ocular trauma

Abstract

Purpose : Open globe injuries, including perforation, laceration, or rupture, are associated with poor visual outcomes due to uncontrolled inflammation/scarring. Steroid drops are a mainstay of post-repair management; however, adherence can be poor and extended use can increase intraocular pressure (IOP). Sutures are the primary means of repair and present an opportunity for local, sustained steroid delivery. We developed nanofiber-based sutures loaded with dexamethasone sodium phosphate (DSP) and tested the hypothesis that they improve wound healing in comparison to nylon sutures in a rabbit model of ocular trauma.

Methods : Electrospinning was utilized to produce nanofibers composed of DSP (8% w/w) and biodegradable polycaprolactone (PCL; 12% w/w) that were twisted and processed to form 9-0-sized multifilament sutures. Sutures were characterized for diameter and strength (n=10) and drug loading/release (n=3). We developed a new model of inflammatory ocular trauma in which normotensive New Zealand White rabbits received an alkali burn followed by a full-depth, 5 mm long corneal incision. Wounds were closed with PCL/DSP or nylon sutures (n=4, each) and monitored for closure, opacity, and neovascularization for 7 days. Results are provided as mean±SD. Statistical analysis was performed using a Student’s t-test.

Results : PCL/DSP suture diameter (33.9±1.5 µm) and breaking strength (0.58±0.05 N) met United States Pharmacopeia requirements for a synthetic, absorbable, 9-0 suture. They demonstrated in vitro release over 7 days and drug loading of 12.6±1.7 µg/cm. In a rabbit corneal burn/incision model, PCL/DSP sutures provided suitable wound approximation without neovascularization (Figure 1) or IOP increase, and significantly reduced peripheral corneal opacity after 7 days (Figure 2) in comparison to nylon sutures (p<0.05).

Conclusions : Nano-structured PCL/DSP sutures met clinical requirements for a 9-0 suture and improved wound healing, demonstrating potential to reduce corneal inflammation without modifying the surgical workflow in ocular trauma repair.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Figure 1. Representative images of rabbit corneas showing improved wound closure and healing using PCL/DSP sutures in comparison to nylon on day 7.

 

Figure 2. Assessment of corneal opacity (0=completely clear; 1=slightly hazy; 2=slightly opaque; 3=opaque; 4=completely opaque) in the (A) center and (B) periphery of the wound on day 7 (*P≤0.05).