Oxidative status and chymotrypsin-like activity in right and left ventricle hypertrophy in an experimental model of emphysema.

ABSTRACT

Although cardiac muscle hypertrophy has been studied in association with several diseases, its mechanism in patients with emphysema, in particular in relation to oxidative stress and proteolysis, remains unknown. The role of oxidative stress and proteolysis in right and left ventricle hypertrophy was investigated in hamsters with emphysema induced by 2 different doses of papain (20mg/mL, E20 and 40mg/mL, E40). The thickness of the ventricles, total and cardiac weight, lipid peroxidation, carbonyl proteins, total antioxidant capacity (TAC), and proteasomal proteolytic activity were evaluated in the right ventricle (RV) and the left ventricle (LV) of control and emphysema hamsters. RV thickness was increased by 12% in the E20 group and by 29% in the E40 group. Lipid peroxidation measured by chemiluminescence was increased in the E40 group (from 3350.68±392.44URL/g tissue to 4696.63±1076.70URL/g tissue, p<0.05). TAC also increased only in the E40 group. In the LV, chemiluminescence values increased from 4044.77±503.39 to 5517.10±388.27 in the E20 group and to 8169.14±1748.77URL/g tissue in the E40 group (p<0.05, both). TAC significantly increased in the E20 and E40 groups. No differences were detected in substances reactive to thiobarbituric acid or carbonyl proteins when comparing ventricles or doses. Chymotrypsin-like proteolytic activity significantly decreased in both groups and ventricles. Emphysema can induce right and left ventricle lipid peroxidation and result in antioxidant mobilization. These data together support the idea that cardiac hypertrophy in response to emphysema is mediated in part by proteolytic pathways with involvement of reactive species.