Treadmill exercise counteracts peripheral inflammation‐inhibited adult hippocampal neurogenesis

Physical exercise has advantageous effects on brain, while inflammation is known to disturb neurogenesis and cognitive function. However, the effects of exercise on peripheral chronic inflammation‐inhibited neurogenesis and learning and memory ability remain unknown. To answer this question, mice were subjected to treadmill exercise with four‐weekly LPS (1 mg/kg/injection, i.p.) treatment and their hippocampal neurogenesis and learning and memory ability were studied. Our results showed that the LPS‐impaired neurogenesis was effectively restored by exercise. Such effect was not due to alteration of LPS‐elicited inflammation. Further analyses suggested that LPS treatment obstructed the neural differentiation pathway, but not the total proliferation rate in the subgranule zone. Exercise, on the other hand, facilitated both the proliferation and differentiation of the neural stem cells. Interestingly, exercise replenished the LPS‐reduced brain‐derived neurotrophic factor (BDNF) and it receptor, TrkB levels. Furthermore, treadmill exercise rescued the LPS‐disturbed performance in water maze. In conclusion, our findings suggest that exercise effectively ameliorates the inflammation elicited neuronal disturbance. The enhanced BDNF and TrkB expression levels may be associated with the exercise‐elicited beneficial effect. This work was supported by National Science council (94‐2321‐B‐006‐005) of Taiwan.