The Effect of Enalapril and Nifedipine on Myocardium and Lung in Chronic Hypoxemia

The aim of this study was to determine the effect of angiotensin converting enzyme inhibitors and calcium channel blockers on myocardium and lung tissue in chronic hypoxic conditions. For this purpose, we have examined the conjugated diene, malondialdehyde (MDA), reduced glutathione (GSH) and total antioxidant (TAA) levels in rats. Twenty Spraque Dawley rats were included in the study. Group 1 rats (n=5) were utilized as sham animals. Group 2 (n=5) rats were used as control animals and they were housed in a hypoxic chamber for 3 weeks. Group 3 (n=5) animals received enalapril 0.2 mg/kg via gastric gavage for 3 weeks while they were kept in hypoxic chamber. Group 4 animals received 0.75 mg/kg nifedipine for 21 days while they were kept in hypoxic condition. All animals were sacrificed at the end of 21 days and their heart and lungs were excised for biochemical determination of tissue damage.
RESULTS
Myocardial and lung conjugated diene, MDA and TAA levels were significantly different in the control group than the nifedipine and enalapril groups (lung conjugated dien, 91.8±5.35 nmol/g in group 2 vs 57.9±5.19 nmol/g in group 3 and 68.7±3.9 nmol/g in group 4, p<0.001; TAA, 4.5±0.3 nmol/g in group 2 vs 5.1±0.1nmol/g in group 3 and 5.2±0.14nmol/g in group 4, p<0.001). There was no significant difference between the enalapril and nifedipine groups. In conclusion chronic hypoxia impairs postischemic myocardial antioxidant reserve and yields to lung damage. Enalapril and nifedipine protects the heart and lungs in chronic hypoxemia against further damage.