Tebuconazole Pesticide Exposure Alters Electrocardiographic Parameters in Pregnant Mice

Cardiovascular diseases (CVDs) are a global health challenge, and emerging risk factors have gained prominence; among them, pesticide exposure is one of the least explored. The population is exposed primarily through the consumption of contaminated food and water. In Brazil, the fungicide Tebuconazole (TEB) is the compound most frequently detected in these products. The maternal-fetal period represents the time of heightened maternal vulnerability to toxic substances. Although maternal toxicity of TEB has been extensively explored, there is no information about cardiotoxic effects during gestational period. Thus, we explore the effects of TEB on maternal cardiac function.  Ten-week-old male and female Swiss Webster mice were mating in a trio (1 male to 2 females).The first 24 hours after confirmation (by vaginal plug checking) were considered the gestational day 0 (GD0). Presumed pregnant mice were dosed daily by gavage. The control group (CTR) received 1 mL/kg of corn oil, while the TEB group received 10 mg/kg/day of the fungicide dissolved in corn oil. During exposure, mothers were weighed on days 0, 7, 11, and 14, and daily from day 17 onward for dose adjustment. Exposure period lasted from GD0 until the day before parturition. After weaning of the pups (~21 days), CTR and TEB mothers were underwent experimental protocols: in vivo electrocardiogram (ECG) and cardiac morphometric analyses. There was no significant difference in body weight gain between CTR and TEB dams during pregnancy. Also, gestational length was no affected by TEB exposure. There was no significant difference in litter size and proportion of male and female offspring between litters from the CTR and TEB groups. On the ECG, dams exposed to 10 mg/kg TEB showed increased QRS complex and QT interval when compared to the CTR group. Also, heart rate was lower in TEB group. Morphometrically, when normalizing heart weight by tibial length or body weight there was no significant difference between the groups. The same was true for the difference in the atria weight. Thus, TEB compromised heart electrophysiology of female mice exposed during gestational period.