Anti-inflammatory effects of topical ocular MAXIDEX administration to rabbits following vitrectomy or lensectomy

We conducted a series of surgical studies (n=155) to find out the possible utility of the Dutch Belted rabbits as an ocular test model. Following either vitrectomy (n=59) or lensectomy (n=96) studies using either BSS or BSS Plus, we characterized the corresponding magnitude and duration of inflammatory response of selected endpoints over a one-week period. Preoperative Dutch Belted rabbits served as controls for baseline determination (n=27). Inflammatory endpoints included clinical inflammation, blood aqueous barrier (BAB) changes measured by particle-scatter and fluorophotometry, corneal edema, and prostaglandin-E2 (PGE2). Topical ocular 0.1% dexamethasone (MAXIDEX) served as a positive treatment group. We compared the inflammatory features (treated and untreated) to determine significance. Using either irrigating solution, the endpoints (n=101) were shown increased in both models. While the clinical scores were similar following both types of surgery (ns; p=0.51), the lensectomy study caused a more marked effect on corneal edema (p=0.0004) and PGE2 production (p=0.002) compared with the vitrectomy study. After the lensectomy procedure, BSS Plus (n=52) compared with BSS (n=24) showed a significant improvement (p=0.004) of clinical score during the recovery phase. Further improvement was gained over BSS Plus (n=52) using MAXIDEX treatment. Topical MAXIDEX (lensectomy, n=20/group; vitrectomy, n=12/group) reduced clinical score (p<0.001), decreased BAB breakdown to fluorescein (p<0.01), lessened particle flare (p<0.05), inhibited aqueous PGE2 levels (p<0.001), and reduced corneal edema (p=0.01) in the lensectomy group. The use of the rabbit model offers a convenient test to identify therapeutic agents that could lessen ocular complications after these common ocular surgeries.