Endurance training mitigates obesity-induced hippocampal impairment by enhancing neurotrophin signalling, synaptic plasticity, and cellular responses in a female rat model

Obesity-related health issues, including cognitive decline linked to hippocampal neurogenesis and neuroplasticity, are gaining more attention as obesity rates rise worldwide. Physical activity is recognized as a potent stimulator of neurotrophic factors. This study examined the impact of six weeks of treadmill training on hippocampal molecular pathways in adult female Zucker diabetic fatty (obese) and Zucker lean rats. Animals were assigned to either treadmill exercise (n = 10) or sedentary control (n = 10) groups. Endurance training (ET) markedly upregulated mRNA expression of brain-derived neurotrophic factor and its receptor. The PI3K/Akt pathway was upregulated only in the trained lean rats and downregulated in the trained obese group compared with sedentary controls. ET elicited divergent effects on neurotrophin-associated PLCγ/PKC/CAMKII signalling between lean and obese groups. Sedentary obese rats primarily utilized the PLCγ/PKC axis, while both trained groups (lean and obese) showed increased CAMKII expression, associated with enhanced synaptic plasticity and memory. Enhanced synaptophysin mRNA indicated improved synaptogenesis and plasticity following ET. Trained obese rats also exhibited reduced expression of the microglial pro-inflammatory marker Iba1, alongside increased markers of oligodendrocyte regeneration and neurofilament expression. Behavioral assessment via the passive avoidance test demonstrated improved learning and memory in trained obese animals. Collectively, these findings suggest that ET may mitigate obesity-induced hippocampal damage, exert neuroprotection, and enhance hippocampal function.