| Objectives To construct three kinds of enriched environment (EE) according to Chinese exercise regimen:preserving the physique EE, preserving the spirit EE, preservation from both physique and spirit EE. To construct a middle cerebral artery occlusion (MCAO)/reperfusion rat model and study the effect of the three kinds of EE on the recovery of neurological function and the expression of SYN and MAP-2in the infarct surrounding and hippocampus areas, and dentritic growth of pyramidal cells of the cerebral cortex. To study the effect of the three kinds of EE on the cognitive function and the expression of SYN and MAP-2, and dentritic growth of pyramidal cells of the cerebral cortex. To clarify the mechanism of preservation from both physique and spirit EE on brain plasticity both from the overall and microscopic level, and enrich the exercise regimen theory of Traditional Chinese Medicine.Methods In this study,128male Sprague-Dawley rats were divided into9groups, they were operation+preserving the physique EE group (MCAO+EE1)?operation+preserving the spirit EE group (MCAO+EE2)?operation+preservation from both physique and spirit EE (MCAO+EE3)?operation+standard group (MCAO+SE) and sham operation+standard group (sham+SE) group,16rats in each group; preserving the physique EE group (EE1)? preserving the spirit EE group (EE2)?preservation from both physique and spirit EE (EE3) and standard group (SE),12rats in each group. MCAO+EE1?MCAO+EE2?MCAO+EE3and MCAO+SE groups were performed the MCAO operation and then were put into the three kinds of EE or standard cages, the sham+SE group were placed1.0cm suture into the internal carotid artery and then put into the standard cages while the E1?E2?E3?SE groups were not performed any operation and put into the three kinds of EE or standard cages after pre-training. The environmental enrollment lasted for14days. In the operation groups, the foot-fault test and the beam-walking test were used to evaluate the functional recovery after MCAO on days3, D3, D7, D10, D14and followed by6-days Morris water maze(M1-M6) while the normal groups did not accept the functional recovery tests. After the Morris water maze, all the rats were sacrificed for histological study, including using the immunohistochemistry method to detect the expression of SYN and MAP-2, and using the Golgi-Cox staining to study dentritic growth of pyramidal cells of cerebral cortex.Results l.The behavioral evaluation was performed on d0, d3, d7, d10, d14of the EE to evaluate the functional recovery. In the foot-fault test, the results of the sham+SE group did not change significantly from test1to5(P>0.05), while the scores of4operation rats gradually reduced, and significantly higher than the sham+SE group (P<0.05). From test3, the MCAO+EE1and the MCAO+EE3groups performed significantly better than MCAO+EE2and MCAO+SE groups (P<0.05); from test4, the MCAO+EE2group performed significantly better than MCAO+SE group (P<0.05). In the last test, the MCAO+EE3group performed significantly better than MCAO+EE1group (P<0.05).The results of the beam-walking test showed that the scores of MCAO+EE3group were significantly higher than the MCAO+SE group from test2(P<0.05), and the scores of MCAO+EE1group were significantly higher than the MCAO+SE group from test3(P<0.05). In the last test, there was no difference between the MCAO+EE3group and the sham+SE group(P>0.05).2. In the first2days of the Morris water maze of the5operation groups, the escape latency was not significantly different among groups (P>0.05). Beginning from day3, rats in the MCAO+EE1and MCAO+EE3groups exhibited shorter escape latency than MCAO+SE group (P<0.05). On day5, the escape latency in the MCAO+EE3group was significantly shorter as compared with that of MCAO+EE1?MCAO+EE2and MCAO+SE groups (P<0.05), while no significant difference was seen between MCAO+EE3and sham+SE groups(P>0.05). In the probe trial, the time spent in the target quadrant of the MCAO+EE3group was significantly more than the other4groups (P<0.05), and the time spent in the target quadrant of the MCAO+EE1group was significantly more than the MCAO+EE2and MCAO+SE groups (P<0.05). Further, no significant group differences were seen in the time spent in the target quadrant between the MCAO+EE1group and the sham+SE group(P>0.05). In the normal groups, the escape latency was not significantly different among groups from day1to day4(P>0.05), while on day5, the EE3group exhibited shorter escape latency than MCAO+SE group (P<0.05). In the probe trial, no significant group differences were seen in the time spent in the target quadrant among the4groups (P>0.05)3. The results of immunohistochemical staining of SYN showed that in the peri-lesional cortex and ipsilateral hippocampus, the sham+SE group had the lowest SYN expression, followed by the MCAO+SE group. There was no difference between MCAO+EE1and MCAO+EE2of SYN expression and significantly lower than MCAO+EE3groups. The expression of MAP-2was significantly lower in MCAO+SE group and MCAO+EE2group compared with MCAO+EE1group and MCAO+EE3group. The MCAO+EE3group had the highest MAP-2expression in the4MCAO groups, and there was no difference between MCAO+EE3group and sham+SE group. In the normal groups, the expression of SYN was the lowest in the SE group, and there was no significant difference of expression between EE1and EE3groups but was significantly higher than EE2group, and the same as the MAP-2expression in the right cortex. In the right hippocampus, the expression of MAP-2was the lowest in the SE group, and there was no significant difference of expression between EE1and EE2groups but was significantly lower than EE3group.4. The results of Golgi-Cox staining showed that comparing with sham+SE group, dentritic branch of pyramidal cells of the undamaged motor cortex and mPFC was significantly greater in the4MCAO groups (P<0.05), while the dentritic branch of the MCAO+EE1and MCAO+EE2groups was significantly greater than the MCAO+SE group (P<0.05), but significantly lower than MCAO+EE3group (P<0.05). Both in motor cortex and mPFC, the spine density was significantly greater in the4MCAO groups comparing with sham+SE group, while the spine density of the MCAO+EE2group was significantly greater than the MCAO+SE group (P<0.05),but significantly lower than MCAO+EE1group (P<0.05). And spine density in MCAO+EE3was significantly greater than all the other4groups (P<0.05). In the normal groups, dentritic branch of pyramidal cells of the left motor cortex in SE and EE2group was the lowest, followed by EE1group, and dentritic branch was the greatest in EE3group (P<0.05), while there was no difference of the dentritic branch among groups in mPFC (P>0.05).Both in motor cortex and mPFC of the intact groups, the spine density of the EE1group was significantly greater than the SE and EE2groups (P<0.05), but significantly lower than EE3group (P<0.05).Conclusions1. The neurological function after cerebral ischemia/reperfusion injury can be partially self-recovered and EE can promote the functional recovery in rats. There was a significant difference of recovery effect among the three kinds of EE, and the "preservation from both physique and spirit" EE had the most significant effects.2.2weeks of EE can promote the expression of SYN and MAP-2in the infarct surrounding and hippocampus areas in cerebral ischemia rats, and the "preservation from both physique and spirit" EE had the most significant effects.3.2weeks of EE can promote the dentritic growth of pyramidal cells of the undamaged motor cortex and mPFC in cerebral ischemia rats, and the "preservation from both physique and spirit" EE had the most significant effects.4.2weeks of "preservation from both physique and spirit" EE can promote the spatial learning ability in normal rats, while2weeks of "preservating physique" EE and "preservating spirit" EE cannot promote the spatial learning ability in normal rats.2weeks of the three kinds of EE cannot promote the memory function in normal rats.5.2weeks of EE can promote the expression of MAP-2and SYN in right cortex and hippocampus areas in normal rats, and the "preservation from both physique and spirit" EE had the most significant effects.6.2weeks of EE can promote the dentritic growth of pyramidal cells of the left motor cortex and mPFC in normal rats, and the "preservation from both physique and spirit" EE had the most significant effects. |
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