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Delayed minocycline inhibits ischemia-activated matrix metalloproteinases 2 and 9 after experimental stroke
Livia S Machado1, Anna Kozak, Adviye Ergul
1Program in Clinical and Experimental Therapeutics, Clinical Pharmacy Department, College of Pharmacy, University of Georgia, Augusta, GA, USA. lmachadogs@students.mcg.edu
Background:
Matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) are increased in the brain after experimental ischemic stroke in rats. These two proteases are involved with the degradation of the basal lamina and loss of stability of the blood brain barrier that occurs after ischemia and that is associated with thrombolytic therapy in ischemic stroke. Minocycline is a lipophilic tetracycline and is neuroprotective in several models of brain injury. Minocycline inhibits inflammation, apoptosis and extracellular matrix degradation. In this study we investigated whether delayed minocycline inhibits brain MMPs activated by ischemia in a model of temporary occlusion in Wistar rats.
Results:
Both MMP-2 and MMP-9 were elevated in the ischemic tissue as compared to the contra-lateral hemisphere after 3 hours occlusion and 21 hours survival (p < 0.0001 for MMP-9). Intraperitoneal minocycline at 45 mg/kg concentration twice a day (first dose immediately after the onset of reperfusion) significantly reduced gelatinolytic activity of ischemia-elevated MMP-2 and MMP-9 (p < 0.0003). Treatment also reduced protein concentration of both enzymes (p < 0.038 for MMP-9 and p < 0.018 for MMP-2). In vitro incubation of minocycline in concentrations as low as 0.1 mug/ml with recombinant MMP-2 and MMP-9 impaired enzymatic activity and MMP-9 was more sensitive at lower minocycline concentrations (p < 0.05).
Conclusion:
Minocycline inhibits enzymatic activity of gelatin proteases activated by ischemia after experimental stroke and is likely to be selective for MMP-9 at low doses. Minocycline is a potential new therapeutic agent to acute treatment of ischemic stroke.
Insights
Minocycline treatment effectively reduced elevated matrix metalloproteinases (MMPs) in the brain following experimental ischemic stroke in rats. This finding suggests minocycline
Area of Science:
- Neuroscience
- Pharmacology
- Biochemistry
Background:
- Matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) are elevated in the brain post-ischemic stroke.
- These proteases contribute to blood-brain barrier instability after ischemia.
- Minocycline is a neuroprotective tetracycline known to inhibit inflammation and matrix degradation.
Purpose of the Study:
- To investigate the efficacy of delayed minocycline administration in inhibiting ischemia-induced MMP activation in a rat stroke model.
- To assess the impact of minocycline on MMP-2 and MMP-9 activity and protein levels.
Main Methods:
- Experimental ischemic stroke induced by temporary occlusion in Wistar rats.
- Intraperitoneal administration of minocycline post-reperfusion.
- Measurement of gelatinolytic activity and protein concentration of MMP-2 and MMP-9 in ischemic brain tissue.
- In vitro incubation of recombinant MMPs with minocycline.
Main Results:
- Both MMP-2 and MMP-9 levels were significantly elevated in ischemic brain tissue.
- Minocycline treatment significantly reduced the gelatinolytic activity and protein concentration of MMP-2 and MMP-9.
- In vitro studies showed minocycline impaired MMP enzymatic activity, with greater sensitivity observed for MMP-9 at lower concentrations.
Conclusions:
- Minocycline effectively inhibits the enzymatic activity of ischemia-activated MMPs, particularly MMP-9, in experimental stroke.
- Delayed minocycline administration shows potential as a therapeutic agent for acute ischemic stroke treatment.
