Fig. 4. Treadmill exercise prevents recognition memory impairment in VD rats. #p<0.05 and##P<0.01 vs. C group;*p<0.05 and **P<0.01 vs. VD group.
Treadmill exercise rescued VD-induced synaptic ultrastructure deficits
Synaptic ultrastructure was the basis of structural synaptic plasticity. Thus, we assessed hippocampal synapse numbers by transmission electron microscope that are critical for the transmission of information related to learning and memory. As shown in Fig. 3, hippocampal synapse numbers were significantly decreased in the VD group compared to the control group (P<0.05; Fig. 5B). These alterations were reversed by treadmill exercise, and the rats exhibited healthier synaptic ultrastructure, including significantly increased synapses and greater synaptic connection density ((P<0.01; Fig. 5B)). Meanwhile, in the Exe group, the number of synapses in the hippocampus were significantly increased than those in C group (P<0.05; Fig.5B). In conclusion, treadmill exercise ameliorated the above damage and protect the ultrastructure of synapses, suggesting improved structural synaptic plasticity.