Age and sex variations in serum brain natriuretic peptide level following doxorubicin-induced myocardial injury in Wistar rats

Abstract

Background: Brain natriuretic peptide (BNP), a cardiac hormone produced by ventricular myocytes, plays an important role in the regulation of blood pressure and fluid volume. Although serum BNP level increases with age in normals, this response and possible sex variations in the presence of drug-induced myocardial injury need to be explored further. Methods: Twenty-four Wistar rats were separated into two groups, the controls and doxorubicin-myocardial injury (DOX-MI) model group. Each group was further subdivided into aged (100–104 weeks) and young (13–14 weeks), having an equal number of males and females (n = 3). The DOX-MI Model group was given 2.5 mg/kg DOX through intra-peritoneal injection on alternate days to a cumulative dose of 12.5 mg/kg. Blood samples were then collected and centrifuged at 3000 g for 15 min and serum BNP analysis was conducted using BNP ELISA Kit (BIOTUVA LIFE SCIENCES, UK). Results: BNP was significantly lower (P = 0.003) in the aged (100–104 weeks) DOX-MI-model group compared to aged controls. Similarly, it was lower in the young (13–14 weeks) DOX-MI-Model group than the young controls, but the difference was not statistically significant (P = 0.16). The analysis between aged and young rats within each group indicated significantly higher BNP levels in the aged rats compared to the young in both groups (P = 0.01 for aged vs. young DOX-MI-Model and P = 0.02 for aged vs. young controls). Conclusion: DOX-induced-MI has caused a significant reduction in BNP production in the aged rats (100–104 weeks) compared to the young (13–14 weeks).