Purpose:To evaluate the effect of increasing storage time on the inhibitory effects of canine and feline plasma on matrix metalloproteinases (MMP) 2 and 9 in vitro. Methods: Matrix metalloproteinases 2 and 9 activity in the presence of canine plasma stored for 57, 155, 222, 316, 367, and 438 days, and feline plasma stored for 17, 198, 565, and 954 days was assayed using a commercially available colorimetric assay kit. Results: For canine plasma, the MMP 2 activity for older samples was not significantly different than the 57-day sample (P = 0.2025-0.9033). Two canine samples had significantly lower MMP 9 activity than the 57-day sample (367 days: P = 0.0099, 438 days: P = 0.0348, others P = 0.0778-0.9928). For feline plasma, storage time did not significantly affect inhibition of MMP 2 and MMP 9 activity (ANOVA, P = 0.2688 and P = 0.2404, respectively). Conclusions: Increasing storage time does not significantly decrease the inhibiting activity of plasma on MMP 2 and 9 for up to 14 months in dogs and 31 months in cats.
K E Y W O R D Scorneal malacia, matrix metalloproteinase inhibition, MMP 2, MMP 9, plasma stability, ulcerative keratitis How to cite this article: Lively MJ, Westermeyer HD. In vitro assessment of the long-term stability of the inhibitory effects of canine and feline plasma on MMP 2 and 9. Vet Ophthalmol. 2019;22:898-901.