Dialysis tubing implant assay in the rat: A novel in vivo method for identifying inhibitors of matrix metalloproteinases
✍ Scribed by John F. DiJoseph; Michele A. Sharr
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 108 KB
- Volume
- 43
- Category
- Article
- ISSN
- 0272-4391
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✦ Synopsis
A novel model to assess the in vivo bioactivity of matrix metalloproteinase (MMP) inhibitors is described. A solution containing the target enzyme, either stromelysin (MMP-3) or collagenase (MMP-1), was put inside dialysis tubing which was then implanted either intraperitoneally or subcutaneously in the back of a rat. The rat was dosed with inhibitor, the dialysis tubing was recovered after a set period of time, and its contents were analyzed for inhibition of enzyme activity. The MMP inhibitors tested were each able to significantly block enzyme activity after either intravenous or oral administration. In vitro, a minimum of 30 min was required for the drugs to maximally equilibrate across the dialysis membrane and inhibit enzyme activity. In the rat, significant inhibition of stromelysin activity was observed at 45 min after intravenous drug administration but was maximal at 60 min. Dialysis tubing of various molecular weight cutoffs from 3,500 to 14,000 did not affect the amount of inhibition exerted by the compounds. The enzyme activity recovered from the dialysis tubing was quantitated by either spectrophotometric or fluorometric assays using specific substrates. This model determined the bioactivity of different chemical classes of known inhibitors of stromelysin and collagenase in a rapid and convenient manner. The dialysis tubing implant model can be expanded to assess the pharmacodynamic bioactivity of a diverse group of drugs using various targets inside the dialysis tubing.