Semaglutide and High-Intensity Interval Exercise Attenuate Cognitive Impairment in Type 2 Diabetic Mice via BDNF Modulation

<b>Background/Objectives</b>: Diabetes frequently leads to cognitive impairment, encompassing issues with memory and executive function, as well as depression and anxiety. This study examines the impact of high-intensity interval exercise (HIIE) alongside glucagon-like peptide-1 receptor agonist (GLP-1 RA) semaglutide on cognitive dysfunction associated with diabetes. <b>Methods</b>: Db/db mice were divided into a control group, semaglutide group, HIIE group, and semaglutide combined with HIIE group to study metabolic and neurobehavioral effects. Cognitive and behavioral tests, hippocampal morphology, and molecular analyses (APP, BDNF, Aβ, p-Tau, PKA, AMPK) were performed. HT22 cells under high glucose were treated with semaglutide, L-lactate, PKA inhibitor H89, and AMPK inhibitor Compound C to validate mechanisms. <b>Results</b>: Over 8 weeks, both HIIE and semaglutide improved neuronal morphology and cognitive performance while reducing depression in db/db mice. However, the current study observed no synergistic effects. Both therapies decreased Aβ and p-Tau protein levels and increased BDNF levels in the hippocampus, likely through the AMPK and PKA signaling pathways, respectively. In vitro, HT22 cells under high glucose conditions exhibited elevated APP and p-Tau expression and reduced BDNF levels, which could be altered by L-lactate and semaglutide. The AMPK inhibitor Compound C and the PKA inhibitor H89 attenuated the increase in BDNF levels induced by L-lactate and semaglutide, but their combination mitigated this inhibitory effect. This study suggests that while HIIE and semaglutide improve cognitive function and reduce depression via BDNF, their combined use did not show the anticipated synergistic benefits due to potential antagonism between the AMPK and PKA pathways. <b>Conclusions</b>: This has important implications for designing exercise prescriptions for cognitive impairment in diabetics.