Longitudinal sex-specific impacts of high-fat diet on dopaminergic dysregulation and behavior from periadolescence to late adulthood.

Objectives: Obesity is recognized for its adverse impact on brain health and related behaviors; however, the specific longitudinal effects of a high-fat diet (HFD) from juvenile stages of development through late adulthood remain poorly understood, particularly sex-specific outcomes. This study aimed to determine how prolonged exposure to HFD, commencing during periadolescence, would differentially predispose male and female mice to an elevated risk of dopaminergic dysregulation and associated behavioral deficits.

Methods: One-month-old C57BL/6J male and female mice were subjected to either a control diet or an HFD for 5 and 9 months. Muscle strength, motor skills, sensorimotor integration, and anxiety-like behaviors were assessed at the end of the 5th and 8th months. Key dopaminergic molecules, including dopamine (DA), dopamine receptor D2 (DRD2), dopamine transporter (DAT), and vesicular monoamine transporter 2 (VMAT2), were quantified at the end of the 5th or 9th months.

Results: Behaviorally, male mice exposed to HFD exhibited more pronounced alterations in sensorimotor integration, anxiety-like behavior, and muscle strength after the 5th month of dietary exposure. In contrast, female mice displayed most behavioral differences after the 8th month of HFD exposure. Physiologically, there were notable sex-specific variations in the dopaminergic pathway response to HFD. Male mice exposed to HFD exhibited elevated tissue levels of VMAT2 and DRD2, whereas female mice showed reduced levels of DRD2 and DAT compared to control groups.

Discussion: These findings indicate a general trend of altered time course susceptibility in male mice to chronic HFD consumption compared to their female counterparts, with male mice impacted earlier than females.