The purpose of this study was to explore the effects of 6-week treadmill exercise on inflammation and neuronal cell death in the hippocampus of intracerebroventricular (ICV) streptozotocin (STZ)-injected Alzheimer's disease (AD) rats. The experimental animals were divided into Sham-CON group (n=10), ICV-STZ CON group (n=10) and ICV-STZ TE group (n=10). The treadmill exercise was conducted for 30 minutes a day, 5 days a week, for 6 weeks. First, in a water maze test, it turned out that the time and distance of finding an escape platform significantly increased in the ICV-STZ CON group as compared to those in the Sham-CON group. In contrast, it turned out that the time and distance of finding the escape platform significantly decreased in the ICV-STZ TE group in which the treadmill exercise was carried out as compared to those in the ICV-STZ CON group. The expression of marker of astrocytes, Glial Fibrillary Acidic Protein (GFAP) increased in the ICV-STZ CON group as compared to that in the Sham-COM group, but that in the ICV-STZ TE group decreased as compared to that in the ICV-STZ CON group. Regarding inflammatory reactions, it turned out that the expressions of TNF-α, IL-1β, Lipocalin-2 and COX-2 increased in the ICV-STZ CON group as compared to those of the Sham-CON group, but it turned out that those of the ICV-STZ TE group decreased as compared to those of the ICV-STZ CON group. Regarding neuronal cell deaths, the expressions of caspase-3 and Bax increased in the ICV-STZ CON group as compared to the Sham-CON group, but it turned out that the expression of Bcl-2 decreased, and the neuronal cell deaths increased. However, it turned out that the neuronal cell deaths decreased in the ICV-STZ TE group in which the treadmill exercise was carried out as compared to that in the ICV-STZ CON group. Therefore, it turned out that the treadmill exercise showed positive effects on improving cognitive ability by reducing inflammatory reactions and inhibiting neuronal cell deaths in the rats with AD. In other words, aerobic exercise like treadmill exercise can be applied as an effective alternative to improve symptoms of AD.
