Maternal obesity induces adverse cardiac programming in offspring, and effective interventions are needed to prevent cardiovascular ill-health. Herein we hypothesized that exposure to maternal obesogenic diet-induced obesity in mice results in left ventricular remodelling and hypertrophy in early childhood, and that maternal N-acetylcysteine (NAC) treatment alleviates these effects in a sex-dependent manner.

The maternal obesity was induced in mice by the consumption of a Western diet accompanied by a 20 % sucrose solution. To determine the effect of NAC on the cardiac outcomes induced by maternal obesity, obese dams were continuously exposed to the obesogenic diet, with or without the oral NAC treatment during pregnancy. Left ventricular remodelling and hypertrophy occurred as early as 7 days after birth in the male offspring of obese dams (O-OB) compared with controls (O-CO). An over-expression of key genes and markers related to cardiac fibrosis accompanied by more disorganized myofibrils was observed in the hearts of neonatal male O-OB mice. When we next evaluated the level of oxidative stress in the hearts of neonatal mice, the activity of enzymatic antioxidants declined and expression of NOX enzyme complex was up-regulated in O-OB offspring hearts, but was normal in the offspring of NAC treated mice (O-OB/NAC). Maternal obesity also activated cardiac Akt and mammalian target of rapamycin (mTOR) signalling in offspring, and NAC treatment restored offspring cardiac Akt-mTOR signalling to normal irrespective of sex. NAC treatment did not prevent cardiomyocyte hypertrophy but did alleviate increased heart weight, interventricular septal thickness, and collagen content in male O-OB/NAC pups.

Collectively, our results indicated that NAC blunted cardiac fibrosis and related ventricular hypertrophy of male neonatal offspring in the setting of maternal obesity, potentially acting by reducing oxidative stress. The present study provides a basis for investigating the role of NAC in nutrition-related cardiac programming.