ABSTRACT
Objective To explore the long-term effects of physical exercise on learning,memory and the expression of plasticity-related gene-1 (PRG-1) in the cerebral cortex of rats with penicillin-induced developmental seizures.Methods Twenty-four 21-day Sprague-Dawley rats were randomly divided into a control group (CONT1),an exercised control group (CONT2),a seizure group (EXP1) and a seizure plus exercises group (EXP2),each of 6 using a random number table.Penicillin was injected intraperitoneally to the rats in the EXP1 and EXP2 groups to induce seizures,while those in the CONT1 and CONT2 groups received saline injections.Morris water-maze tests were performed to evaluate spatial learning and memory capacity.The rats in the CONT2 and EXP2 groups were administered an aerobic exercise program 30 min per day for 6 consecutive days.The other groups were maintained on the treadmill for the same time but without exercising.Real-time polymerase chain reactions were used to quantify the expression of PRG-1 mRNA in the cerebral cortex.Results There was a decreasing trend in marginal searching and increasing taxis and linear searching in all four groups.Ridit analysis showed that in the watermaze tests on days 2 and 4 the average scores of the control groups were significantly higher than those of the EXP1 and EXP2 groups.However,significant increases in the average scores were observed in the maze tests of the EXP1 group after day 2 and with the EXP2 group from day 4 on.The average scores of the control group were significantly lower than those of the other 3 groups.In the first maze test,the average memory scores of the two seizure groups were significantly lower than those of the controls.In the second maze test,however,only the EXP1 group's average score was significantly worse than those of the other groups.That of the EXP2 group had improved significantly,and was not significantly different from that of the CONT2 group.The expression of PRG-1 was much higher in the CONT2,EXP1 and EXP2 groups than in the CONT1 group.The average expression of PRG-1 in the EXP2 group was not significantly different from that in the EXP1 group.Conclusions Physical exercise can significantly relieve the cognitive deficits induced by long-term seizures,which may be associated with the regulation of PRG-1 expression in the cerebral cortex.
ABSTRACT
ObjectiveTo observe Semaphorins-3A and synaptophysin P38 expression in hippocampus of developing rat induced by status epilepticus.Methods 320 SD rats were divided into four groups (P7,P14,P21 and P28) according to day -old after birth (7d,14d,21d and 28d).Rats in each group were randomly divided into model group (SE group) and saline control group (NS group).SE was induced by Pentylenetetrazol (PTZ).Semaphorins-3A and synaptophysin P38 expression were determined by immunohistochemical staining on 1d,7d,14d,21d and 28d after SE in hippocampal CA1 of rats.ResultsSemaphorins-3A-positive cells could be seen in the hippocampal granule cell layer in all rats.Semaphorins-3A expression tended to decrease with the increasing of day-age,especially in P7 group(91 552.68 ± 4664.69 ).No matter how day-age,Semaphorins-3A expression was similar to that in NS group and was obvious reduced in 7d after SE(56 938.84 ± 5688.47 ).Meanwhile P38 expression in P7-day-age rats had had been gradually increasing between 1 day and 14d (5413.18 ±48.77,6223.40±29.19,6902.94 ±78.51 ) and then stabilized gradually on 21d(7523.42 ± 62.94) after rats were tested.P38 expression in other day-age rat was relatively stable on the same level in physiological state.On the other hand P38 expression in the hippocampal CA1 region of P7,P14,P21 and P28 rats was significantly higher than that in normal rats between 1day and 28day after SE episode(P＜ 0.05 ),and reached a peak on 14 day(8408.35 ± 55.73 ).ConclusionSemaphorins-3A and synaptophysin P38 involved in hippocampal synaptic plasticity of rat in developing stage and epilepsy.
ABSTRACT
Objective To study the distribution and expression of Semaphorins-3A protein in brain of postnatal rats.Methods Semaphorins-3A positive cells were observed by immunohistochemistry in the cerebral cortex,hippocampus,dentate gyms and entorhinal cortex in postnatal 0d,7d,14d,21 d and 28d of Sprague Dawley rats.Results Semaphorins-3A positive cells widely distributed in the granule cell layer ( Ⅱ ),external pyramidal cell layer ( Ⅲ ),internal granular cell layer ( Ⅳ ),pyramidal cell layer ( Ⅴ ) and layer of polymorphous cells ( Ⅵ ),in addition to the molecular layer ( Ⅰ ) of the parietal,occipital,frontal,temporal,insular,cingulate cortex,piriform cortex and entorhinal cortex with postnatal 0d,7d,14d,21d and 28d rats.The amount of semaphorins-3A positive cells(IOD) in the entorhinal cortex was 84916.23 ± 3266.34 in P0d,77711.41 ± 2634.26 in P7d,74124.25 ± 3989.09 in P14d,65887.63 ± 3406.57 in P21d and 57705.96 ± 3136.35 in P28d,meanwhile the region of semaphorins-3A positive cells narrowed in the part level with Ⅱ -Ⅵ levels of cortex.Similarly semaphorins-3A positive cells distributed mainly in granule cell layer of dentate gyrus,CA1,CA3 region and only a few of semaphorins-3A positive cells scattered in the multi-line layer in hippocampus.The expression level of semaphorins-3Awas significant difference among postnatal 0d,7d,14d,21d and 28d rats (P＜0.01).Conclusion Semaphorins-3A positive cells widely distribute in the various cortex and hippocampus in developing rat brain,and the region of semaphorins-3A is reduced with age growth of rats.
ABSTRACT
Objective To observe neural stem cells proliferation,migration and differentiation in hippocampus in developing rats with status epileptictus.Methods 320 healthy SD rats at age 7,14,21,28 d (P7,P14,P21,P28) were randomly divided into status epilepticus (SE) and normal control group.In each group those rats at the same age were further randomly divided into 1,7,14,21,28 d five time points after PTZ-induced SE (n =8).New cell proliferation and migration were observed by immunohistochemistry studies in the dentate gyms.Double labeling with Brdu/NeuN and Brdu/GFAP was performed in the P14 rats.Results Nestin positive cells appeared in the dentate gyms on 1 d after SE in P7,P14,P21,P28 rats.The number of nestin positive cells gradually increased on 7 d and reached a peak on 14 d,then gradually reduced on 21 d,finally fell to a minimum on 28 d after SE.The numbers of nestin positive cells on 7 d(177.00 ± 3.22,t =16.033) and 14 d (195.00 ± 3.41,t =28.840) were significantly higher in the SE group than the NS group (147.50 ± 2.08,136.50 ± 2.65,both P ＜ 0.05).The smaller age of rats with SE onset,the greater the nestin intensity.But the number of nestin positive cells in the dentate gyrus of normal rats were gradually decreased with increasing age.Nestin positive cells were distributed in subgranular zone of dentate gyrus on 1 d and 7 d after SE,then gradually migrated to the granule cell layer on 14 d with morphological changes.Small part of nestin positive cells were ectopically migrated to the hilus of dentate gyrus in P14,P21,P28 age rats,and were also seen in the CA1,CA3 of hippocampus and cortex with various cell morphology.For differentiation of newly generated cells,most of Brdu positive cells coexpressed NeuN and about 4％-5％ cells co-expressed GFAP.Conclusions SE could induce neurogenesis in the hippocampal dentate gyrus area in developing rats which has age-related characteristics.Most new cells migrate from the subgranular zone to the granule cell layer of the dentate gyrus,and a small number of newly generated cells ectopically migrated to the hilus of dentate.The majority of newly generated cells differentiate into neurons,and the others differentiate into glial.