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Lab Research
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A Simple Method for Estimating the MMP Inhibition Potential of Collagen Dressings First Author: Yuehua Xiao Authors: Val DiTizio and Frank DiCosmo Introduction: A commercially available assay* can be used to evaluate the collagenase inhibition ability of collagen-based wound dressings by co-incubation of samples with the enzyme. The quantity of released fluorescent peptides from the self-quenched gelatin substrate is proportional to the collagenase activity. The primary objective of the study was to demonstrate the viability of the assay system using several collagen-based products. Method: The wound dressings evaluated were a collagen/alginate dressing, a collagen/oxidized regenerated cellulose dressing with silver, and a novel dressing containing denatured collagen, alginate, carboxymethylcellulose, and a metal chelator with and without silver. Samples of wound dressings (usually ca. 10 mg ea.) were incubated with collagenase (Clostridium histolyticum) solutions at 37ûC. At selected intervals (0, 2, 4, and 6 hr) an aliquot of the solution was removed to a separate container. Subsequently, the fluorescently-labeled gelatin substrate and reaction buffer were added to the collagenase aliquots. Sample solutions were incubated at room temperature overnight. Collagenase activity was estimated by measuring solution fluorescence at 515 nm using an excitation wavelength of 495 nm. Results: The use of the collagen/alginate dressing did not lead to inhibition of collagenase activity as determined by relatively similar fluorescence levels after 6 hours of incubation when compared to a no-dressing control. However, enzyme solutions co-incubated with the remaining dressings all displayed substantially reduced fluorescence, which is indicative of reduced collagenase activity. Conclusions: The modified collagenase/gelatinase assay described above was able to detect collagenase inhibition in dressings specifically designed to inhibit matrix metalloproteinases (MMP). The lack of inhibition observed with the collagen/alginate dressing suggests that collagen alone may not be sufficient to inhibit MMP activity. *EnzChek ª Gelatinase/Collagenase Assay Kit |
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