Background/Objectives: Goto-Kakizaki (GK) rats exhibit insulin resistance and type 2 diabetes mellitus (T2DM) without obesity. This study explored the effects of ω-3 fatty acid supplementation on T lymphocyte polarization in Wistar (WT) and GK rats. Methods: They were administered ω-3 fatty acid-rich fish oil (FO) containing eicosapentaenoic (540 mg/g) and docosahexaenoic acids (100 mg/g) by oral gavage at 2 g/kg, thrice a week for 8 weeks. The control groups (WT CT and GK CT) received the same volume of water. The following groups were investigated: GK CT, n = 14; GK ω-3, n = 15; Wistar CT, n = 15; and Wistar ω-3, n = 11. Glucose and insulin tolerance tests (GTT and ITT) were performed. Fasting plasma insulinemia and glycemia were measured. After euthanasia, the lymphocytes were extracted from the mesenteric lymph nodes. Results: The results showed that GK rats supplemented with FO had significantly improved glucose tolerance and insulin sensitivity (kITT). It also promoted greater polarization of lymphocytes toward T regulatory (Treg) features and a reduction in Th1 and Th17 profiles. Additionally, the GK ω-3 group exhibited lower cell proliferation, decreased pro-inflammatory cytokines, and increased IL-10 levels compared to the GK control. Conclusions: In conclusion, FO supplementation benefited GK rats by improving glucose intolerance, suppressing insulin resistance, and modulating lymphocytes toward Treg polarization.

Brain glucose hypometabolism and neuroinflammation are early pathogenic manifestations in neurological disorders. Neuroinflammation may also disrupt leptin signaling, an adipokine that centrally regulates appetite and energy balance by acting on the hypothalamus and exerting neuroprotection in the hippocampus. The Goto-Kakizaki (GK) rat is a non-obese type 2 diabetes mellitus (T2DM) animal model used to investigate diabetes-associated molecular mechanisms without obesity jeopardizing effects. Wistar and GK rats received the maintenance adult rodent diet. Also, an additional control group of Wistar rats received a high-fat and high-sugar diet (HFHS) provided by free consumption of condensed milk. All diets and water were provided ad libitum for eight weeks. Brain glucose uptake was evaluated by 2-deoxy-2-[fluorine-18] fluoro-D-glucose under basal (saline administration) or stimulated (CL316,243, a selective β3-AR agonist) conditions. The animals were fasted for 10-12 h, anesthetized, and euthanized. The brain was quickly dissected, and the hippocampal area was sectioned and stored at -80°C in different tubes for protein and RNA analyses on the same animal. GK rats exhibited attenuated brain glucose uptake compared to Wistar animals and the HFHS group under basal conditions. Also, the hippocampus of GK rats displayed upregulated leptin receptor, IL-1β, and IL-6 gene expression and IL-1β and the subunit of the transcription factor NF-κB (p-p65) protein expression. No significant alterations were detected in the hippocampus of HFHS rats. Our data indicated that a genetic predisposition to T2DM has significant brain deteriorating features, including brain glucose hypometabolism, neuroinflammation, and leptin signaling disruption in the hippocampal area.

We determined the prevalence of metabolic syndrome (MetS) among military police officers (MPOs) from the radio patrol program of the Military Police of Sao Paulo State (PMESP). Towards this goal, we analyzed the following characteristics: shift duty (daytime or nighttime patrol), service length in the PMESP, education level attained, weekly alcohol consumption, smoking, and physical activity of 93 MPOs. The MPO groups were created based on work shift [daytime (n=48) or nighttime (n=45)], and years of MPO experience [≤3 years (n=48) or ≥10 years (n=45)]. The overall prevalence of MetS among the 93 MPOs was 43%. There was a higher prevalence of MetS in the group with ≥ten years (53.3%) than that with ≤three years (33.3%); so, 1,6 times higher. The more prevalent MetS indicators (n=93) included waist circumference (76.3%), hypertension (55.9%), reduced plasma HDL-cholesterol levels (44%), hypertriglyceridemia (32.2%), and hyperglycemia (20.4%). Greater waist circumference, hypertension, hypertriglyceridemia, higher glycated hemoglobin A1c (HbA1c) levels, and MetS itself were associated with the service length (i.e., ≥ten years). The work shift was not associated with any MetS indicator. Those who were overweight or obese were 2.2. times more likely to develop MetS. Hypertriglyceridemia, the best indicator of the MetS, increased the chance of developing MetS by 16 times. Conclusion: MPOs exhibit a high prevalence of MetS, associated with the years of service and age.