Fig. 2. Expression of molecular markers in the left ventricle of hearts subjected to pressure overload hypertrophy.
A, Northern blot hybridization of total RNA from the left ventricle of sham and TAC C57BL/6J mice shows an increase in expression of atrial natriuretic peptide (ANP) and skeletal α actin (Sk. α-actin). The bar graph shows the densitometric analysis of the relative ANP expression versus β-actin. Although the Northen blot shows samples from each group in duplicate, the relative values were obtained from experiments in triplicate, values are means ± s.e.m * p < 0.05 is statistical significant. B, as above, Northern blotting was done using the same DNA probes in RNA samples from left ventricle of ob/ob mice of sham and TAC groups. A blunted response of ANP expression during TAC is observed in ob/ob mice hearts. Chronic intraperitoneal administration of leptin triggered the expression of ANP in ob/ob mice subjected to TAC. Statistical analysis of the relative densitometric values for ANP expression versus β-actin was performed as before. The values were obtained from triplicate experiments. One way Anova and Bonferroni’s test were used. Values are means ± s.e.m * p < 0.05 is statistically significant. S, sham; TAC, trans-aortic constriction, TAC + L, trans-aortic constriction and intraperitoneal injection with leptin 0.3 mg/kg/ per day.