Depression is one of the most prevalent psychiatric disorders. Exercise has been shown to be effective in the amelioration of depression, but the underlying mechanism remains largely unknown. Alterations in the density and morphology of dendritic spines are associated with psychiatric diseases. Chronic unpredictable mild stress (CUMS) is an established animal model of depression. The aim of this study was to determine whether treadmill exercise reverses CUMS-induced both depression-like behaviors and alterations in spine density and morphology of the principal neurons in the brain areas of the mood circuits including the hippocampus, medial prefrontal cortex (mPFC), nucleus accumbens (NAc) and basolateral amygdala (BLA). Male rats were randomly divided into four groups: control, CUMS, exercise, and CUMS+exercise. CUMS-induced depression-like behaviors were evaluated by the sucrose preference test (SPT). Golgi staining was used to visualize dendritic spines. Our results showed that CUMS-induced depression-like behaviors characterized by a decrease in sucrose consumption were accompanied by a decrease in spine density and a change in spine morphology in the pyramidal neurons of both the hippocampal CA3 area and the mPFC, and an increase in spine density and an alteration in spine shape in both the NAc medium spiny neurons (MSNs) and the BLA neurons; exercise reversed both CUMS-induced depression-like behaviors and alterations in dendritic spines. This study provides important information for understanding the mechanism through which exercise ameliorates CUMS-induced depression-like behaviors.

Introduction/PurposeDiabetes is a leading cause of morbidity and mortality and is more prevalent in Blacks and Hispanics. This study aims to examine if different physical activity (PA) intensities reduced hemoglobin A1c (HbA1c) in Blacks and Hispanics with type 2 diabetes mellitus (DM2).MethodsThis pilot study used a one-sample pre- and postintervention design, including four in-person visits during a period of 3 months from January 2018 to December 2020 in Black or Hispanic populations with DM2 in the Greater Hartford, Connecticut, area. At each in-person visit HbA1c; specific, measurable, achievable, realistic, and time-bound goals; and daily PA (categorized into high-, moderate-, or low-intensity levels by a Fitbit® Charge 2) were obtained. Change scores for minutes engaged in each PA level and HbA1c values were created between visits. A linear mixed model was used to analyze these relationships over time.ResultsAmong 17 completed participants, mean age was 56 yr, 11 were Black, 6 were Hispanic, 13 were female, and 4 were male. At baseline, mean body mass index was 34.8 kg·m−2 and mean systolic/diastolic blood pressure was 135/81 mm Hg. From 70.2 mmol·mol−1 at baseline, HbA1c decreased to 66.3 after 4 wk, 66.0 after 8 wk, and 63.5 by 12 wk (9.5% reduction, P < 0.05). Average daily PA time increased over 3 months from 15.8 to 20.3 (P = 0.04) to 20.8 (P = 0.02) minutes for moderate-intensity PA (P = 0.05), and from 12.1 to 13.6 (P = 0.08) to 15.2 (P = 0.01) minutes for high-intensity PA. PA increases were significantly associated with an overall 0.58% reduction of HbA1c (P = 0.04).ConclusionGuided by carefully selected, evidenced-based behavioral change strategies, this study found that increases of ~7 min of moderate- or high-intensity daily PA were associated with ~10% decrease in HbA1c in Blacks and Hispanics with DM2. This is consistent with the current consensus statement from the American College of Sports Medicine.

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