Evaluation of various compounds to inhibit activity of matrix metalloproteinases in the tear film of horses with ulcerative keratitis.

The research article analyzes the effects of antiproteolytic compounds on the activity of certain enzymes in the tear film of horses with corneal ulcers.

Overview of the Study

• The study was designed to examine the in vitro effects of several antiprotelytic compounds on the activity of matrix metalloproteinase (MMP)-2 and -9. These enzymes are present in the tear film formulations of horses suffering from active corneal ulcers.

Methodology

• The tear film samples for this study were acquired from 34 horses diagnosed with active ulcerative keratitis.
• These horses were sedated during sample collection. The samples were gathered from the lower fornix of their ulcerated eyes using capillary tubes.
• The compounds that were used to treat the pooled samples included 0.2% EDTA, 0.1% doxycycline, 10% N-acetylcysteine (NAC), 0.1% solution of modified dipeptide ilomostat, 0.1% alpha1-proteinase inhibitor (PI), 0.5% alpha1-PI, and 100% fresh equine serum (ES).
• To measure the quantity of latent and active MMP-2 and -9, the researchers performed optical density scanning of gelatin zymograms of the treated and non-treated tear samples.

Findings of the Study

• The researchers discovered that the pooled tear samples obtained from ulcerated eyes held both latent and active forms of MMP-2 and -9.
• Compared to the MMP activity in the untreated samples, total MMP activity was substantially reduced in the treated samples. EDTA reduced activity by 99.4%, Doxycycline by 96.3%, NAC by 98.8%, Ilomostat by 98.9%, 0.1% alpha1-PI by 52.4%, 0.5% alpha1-PI by 93.6% and ES by 90.0%.

Conclusions

• The study concluded that the tested compounds – EDTA, doxycycline, NAC, ilomostat, alpha1PI, and ES – were successful in inhibiting the MMP activity in vitro.
• Since these compounds work differently to inhibit various families of proteases in the tear film of horses, combining these protease inhibitors could potentially improve the treatment of corneal ulcers in horses.