Abstract
The majority of stroke patients suffer long-term disabilities impacting both motor and cognitive function. Physical exercise has been shown to improve functional recovery following focal cerebral ischemia by facilitating brain plasticity. However, the exercise intensity that promotes optimal cognitive recovery needs closer examination. This study seeks to analyze the effects of forced treadmill exercise at various speeds on spatial memory tests after focal ischemia in rats. We hypothesized that, a moderate intensity treadmill regiment will better ameliorate cognitive deficits and improve functional recovery after focal ischemia compared to the high or mild intensity groups. Three-month-old male Sprague Dawley rats were acclimated to the investigator and treadmill for three days. On day four, rats underwent focal cerebral ischemia using the middle cerebral artery occlusion model for 90 minutes or sham surgery and were randomly assigned to an exercise intensity group. Rats had three days of recovery post-surgery followed by forced treadmill exercise for six days. The rats were exposed to a two-minute warm-up period at 5 m/min and then exercised for a period of 30 minutes at 6 m/min for mild, 10 m/min for moderate, and 18 m/min for heavy. Finally, the rats were subjected to contextual fear conditioning where rats were placed in a fear conditioning chamber for 8 minutes with a 2 second 1.5 mA shock delivered at minute 7.5 then returned to chamber 24 hours later. Fear conditioning data showed that, following a stroke rats froze 16.48 +/- 2.75%, compared to the moderate intensity group where rats froze 63.57 +/- 10.72 % (S.E.M, n = 10, p < 0.01, one-way ANOVA, Bonferroni post-hoc). Mild and heavy exercise groups froze 43.3 +/- 10.75% and 38.26 +/- 10.53% respectively. In conclusion, focal cerebral ischemia impairs cognitive function, however moderate intensity physical exercise has the most beneficial impact on cognitive recovery compared to other exercise intensities.