Alterações cardíacas da prole de animais expostos à poluição do ar: impacto do treinamento físico

Abstract

Air pollution poses one of the main threats to public health and is associated with cardiorespiratory diseases. Although some gestational effects of exposure to fine particulate matter (PM2.5) have already been described, its impacts on the cardiovascular system of offspring, as well as the role of exercise training in this context, remain unknown. This study aimed to investigate the effects of exercise training on cardiac, autonomic, and inflammatory morphofunctional parameters in the offspring of both sexes of Wistar rats exposed to PM2.5 during pregnancy. The mothers were exposed to PM2.5 in a particle concentrator from the 5th to the 21st day of gestation. The offspring were divided into male (M) and female (F) groups (n=6–8 per sex/group): controls (CM, CF), exposed (EM, EF), and exposed-trained (TM, TF). Exercise training (8 weeks, 40–60% of maximum speed) was initiated after weaning, followed by assessments of cardiac morphology and function by echocardiography, heart rate variability (HRV) using linear and nonlinear methods, and systemic inflammation by ELISA. Prenatal exposure led to a reduction in left ventricular end-diastolic diameter (LVEDD;d) and increased IL-6 and IL-6/IL-10 ratio in both sexes. In the EM group, a reduction was observed in left ventricular (LV) mass as assessed by echocardiography and tissue wet weight, as well as in mitral annular velocity during systole (S’) and during late ventricular filling (A’), accompanied by an increase in the LV early-to-late filling ratio (E/A). In the EF group, there was a reduction in pulse interval variance (Var IP). Exercise training increased functional capacity, ejection fraction (EF), Var IP, and the vagal component (HF), while reducing TNF-alpha, IL-6, the IL-6/IL-10 ratio, and the SD2/SD1 ratio (instantaneous/long-term standard deviation) in both sexes. Specifically in the TM group, there was an increase in the thickness of the septum (IVS;d) and the posterior wall (PPVE;d) of the LV, with a reduction in isovolumetric relaxation time (IVRT) and the myocardial performance index (MPI). In the TF group, an increase in IVS;d, S’, and IL-10 was observed. In Pearson correlation analyses, a negative correlation was observed between Var IP and IL-6/IL-10 (r = -0.62; p = 0.0014), as well as between IL-6/IL-10 and LV mass (r = -0.76; p = 0.0001) and with IPM (r = -0.79; p = 0.0001), suggesting an interaction between autonomic dysfunction, inflammatory imbalance, and structural and functional cardiac impairment. Prenatal exposure to PM2.5 caused persistent morphofunctional and inflammatory changes, with males showing greater susceptibility. Aerobic exercise training attenuated these dysfunctions, exerting a cardioprotective and preventive role in the offspring.