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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.
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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.
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Objective To observe the effect of Ro 20-1724 on social interaction ability of developing rats after repeated ketamine anesthesia.Methods 32 rats with 21 days old were randomly divided into four groups,control group (C group),ketamine group (K group),ketamine + Ro 20-1724 group (K + R group),ketamine + ethanol group (K + E group).Ethanol was used as a solvent of Ro 20-1724.Ketamine 70 mg· kg-1 was intraperitoneal injected,30 min later,to give or not give Ro 20-1724 0.5 mg · kg-1 or equivalent ethanol solvent for once each day for seven consecutive days.Then the rats were fed for three days.On the fourth day after the last administration,the social interaction ability were assessed in all rats.The expression of brain-derived neurotropic factor (BDNF) in hippocampal CA1 region was detected using conventional ELISA.Results Comparing with rats in C group,the time spent on the cage of lifeless body ((60 ± 29) min vs (109 ± 33) min,P ＜ 0.01),unfamiliar rats (103 ±35)min vs (151 ±42)min,P＜0.01;((123 ±34)min vs (184 ±46) min,P＜0.05) and familiar rats (89 ± 25) min vs (140 ± 38) min,P ＜ 0.01) in the social interaction test was significantly less in K group.The time spent significantly prolonged in group K + R,comparing with K group (lifeless body:(94 ± 34) min vs (60 ±29) min,P＜0.01) ;unfamiliar rat 1:(140 ±41) min vs (103 ±35)min,P＜0.05) ;unfamiliar rat 2:(171 ±45)min vs (123 ±34)min,P＜0.01) ; familiar rat:(133 ±35)min vs (89 ±25) min,P＜0.01).And there was no difference between K group and K + N group (P ＞ 0.05).The expression of BDNF in hippocampal CA1 region was significantly lower in K group,comparing with C group ((8.6 ± 2.7) ng/ml vs (11.8 ± 2.4) ng/ml,P ＜0.01) ; and there was a significant increase in K + R group,comparing with K group ((10.1 ± 3.6) ng/ml vs (8.6 ± 2.7) ng/ml,P ＜ 0.05).Conclusion Ro 20-1724 significant rescued social interaction impairment induced by ketamine anesthesia in developing rats.And BDNF in hippocampal CA1 region contribute to the reversal process.
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Malnourished pups were obtained by increasing litter size to 20 pups/dam VS 10 pups/dam in controls. Rehabilitation was started when the pups were 17 days old. The normalized growth rate (% body weight increase/day) of the malnourished pups was significantly lower than that of controls at 10-17 days of age. After starting ad libitum feeding, the normalized growth rate became the same as that of control when both groups were at 17-23 and 23-34 days of age. The body weight of the previously malnourished pups was still lower than that of controls at 34 days of age. Serum growth-promoting activity (GPA) in malnourished and control rat pups was determined by measuring the degree of stimulation of thymidine incorporation into lymphocytes treated with low dose of phytohemagglutinin (PHA). The serum GPA in malnourished pups was lower than that of controls at 17 days old. When malnourished pups were weaned onto laboratory chow ad libitum starting at 17 days, their serum GPA at 23 and 34 days of age was found to be similar to that of control pups of the same age. We conclude that immediate postnatal malnutrition is associated with reduction of serum GPA and reduced growth.
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Serum growth-promoting activity (GPA) in rats was determined by measuring the degree of stimulation of thymidine incorporation into lymphocyts treated with low dose of phytohemagglutinin (PHA). GPA in rat serum was found to be low at birth (193% of that stimulation with PHA alone), increased slightly (224%) at 5 days of age and then increased rapidly to peak at 10 days of age (450%). Thereafter, GPA decreased gradually, reaching an adult level (which was similar to that of the newborn) at 60 days of age. A significant correlation was found between the level of GPA and normalized growth rate (% body weight increase/day) in rats.