Effects of foraging exercise on behavior and the expression of 5-hydroxytryptamine 1A and transforming growth factor β1 in the frontal lobes of rats modelling post-stroke depression / 中华物理医学与康复杂志

ABSTRACT

Objective:To explore the effect of foraging exercise (FE) on the behavior of rats with post-stroke depression (PSD) and the expression of 5-Hydroxytryptamine 1A (5-HT1A) receptor and transforming growth factor β1 (TGF-β1) in their frontal lobes.Methods:Thirty-six healthy male Sprague-Dawley rats were randomly divided into an ischemia-reperfusion (I/R) group, a PSD group and a PSD+ FE (FE) group, each of 12. The right middle cerebral artery of each was occluded using the thread occlusion method with 1.5h of ischemia. In the PSD and FE groups, mild stimulation was administered at unpredictable intervals over 3 weeks beginning 1 week after the successful modeling. The rats in the I/R group were raised in a group. Those in the PSD group were raised in individual cages. Those in the FE group were raised in a single cage and foraged freely for a total of 4 weeks. Four and eight weeks after the modeling, the body weights were measured, and the open field, social interaction (SIT) and sugar preference tests were administered to all of the groups. Four weeks later, all of the rats were sacrificed and their brains were sliced and stained. The expression of 5-HT1A receptor and TGF-β1 in the frontal lobe was detected using western blotting.Results:One week after modeling, there was no significant difference in average body weight or the average behavioral scores among the three groups. After four weeks the PSD and FE groups had significantly lower average body weight than the I/R group, fewer counts of rearing and grid crossing, longer SIT latency, less interaction time and lower average sugar preference (all significant differences). After eight weeks the average body weight had increased in each group. SIT latency had shortened and interaction time had increased in the FE group, and the rearing and grid crossing counts and sugar preference had increased in the PSD and FE groups. At that point the FE group had significantly greater average body weight than the PSD group, more counts of rearing and grid crossing, shorter SIT latency, increased interaction time, and greater sugar preference. The ratio of residual brain volume in the right hemisphere of the PSD and FE groups was significantly lower on average than in the I/R group. However, there was no significant difference in the right residual brain volume ratio between the PSD and FE groups. Staining revealed that the pathological changes in the frontal lobes of the FE group had been significantly relieved compared with the PSD group. Eight weeks after the operation the increases in average 5-HT 1A receptor and TGF-β1 levels in the FE group were significantly greater than in the PSD group.Conclusion:Foraging can relieve the depressive symptoms of rats modeling post-stoke depression. The mechanism may be related to alleviating the pathological damage and increasing the expression of 5-HT1AR and TGF-β1 in the frontal lobe. Early chronic stress may increase the volume of cerebral infarction, at least in rats.