Instructions: Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.
Input: Context: Although matrix metalloproteinase (MMP) activity increases, endothelial function decreases after myocardial infarction (MI). The antibiotic doxycycline inhibits MMP activity in vitro. The role of doxycycline-mediated MMP inhibition in endothelial function is unclear.', 'Doxycycline ameliorates endothelial dysfunction, in part, by inhibiting MMP activity.', 'We subjected Sprague-Dawley male rats to MI by ligating the left anterior descending arteries. We subjected another group of rats to sham surgery. We administered doxycycline in drinking water (0.67 mg/ml) to both groups 2 days before surgery: the sham group underwent sham surgery and received doxycycline therapy, and the MI group underwent MI and received doxycycline therapy (n = 6 in each group). After 4 weeks, we anesthetized rats and prepared left ventricular rings from infarcted-ischemic (I), non-infarcted near-infarcted (NI), and sham surgery hearts with and without doxycycline treatment.', 'The MMP-2 activity increased significantly in I and NI hearts, and we observed a selective increase in MMP-9 activity only in I hearts, when compared with other groups (p < 0.05), measured by zymography. Cardiac inhibitor of metalloproteinase decreased only in I hearts (p < 0.05 vs other groups), measured by Western analysis, and doxycycline treatment reversed this decrease. Contractile response of rings to acetylcholine was attenuated in the I group, suggesting nitric oxide-mediated dysfunction, and was reversed by doxycycline. The response to nitroprusside was attenuated in I hearts and ameliorated by doxycycline, suggesting cardiomyocyte dysfunction. Bradykinin induced relaxation in rings from sham surgery hearts and from NI hearts, but induced paradoxic contraction in rings from I hearts. Treatment with doxycycline reversed the paradoxic contraction.
Answer: Results suggest a protective action of doxycycline in the ischemic heart, possibly because of additional pharmacologic actions such as metalloproteinase inhibition.
Output:
Does doxycycline ameliorate ischemic and border-zone remodeling and endothelial dysfunction after myocardial infarction in rats?