RESUMO
Objective To establish drug resistant models of temporal lobe epilepsy induced by amygdala kindling,and to investigate the changes of cAMP response element binding protein (CREB) and phosphorylated cAMP response element binding protein (p-CREB) expression in the hippocampus tissues in order to explore their roles in drug resistant epileptogenesis.Methods Eighty adult male SD rats were randomly divided into control group (n =10) and model group (n =70).The 70 rats were used to prepare the amygdaloid kindled model of epilepsy by chronic stimulation of amygaloid basal lateral nucleus.The successful kindled models were randomly selected as drug resistant epileptic group (n =10) and drug sensitive epileptic group (n =10) according to their response to the phenytoin and phenobarbital.On the basis of behavioral observation,electrophysiology,pathological HE staining,CREB and p-CREB expression changes,we verified the reliability of the models and explored the differences among the three groups above.The changes of CREB and p-CREB expression were detected by immunohistochemical method and Western blotting assay.Results In control group,the electroencephalogram (EEG) frequency was (8.700 ±1.494) Hz;in drug sensitive epileptic group,the EEG frequency was (14.700 ± 1.159) Hz;in drug resistant epileptic group,the EEG frequency was (19.800 ± 1.686) Hz.The frequency differences among the three groups were statistically significant (F =144.202,P =0.000).By immunohistochemical staining,a large number of CREB and p-CREB positive cells were observed in drug resistant epileptic group.As compared with the control group (CREB 0.197 ±0.058,p-CREB 0.260 ±0.176),the expression levels of CREB and p-CREB were increased in drug sensitive epileptic group (CREB 0.361 ±0.151,p-CREB 0.656 ±0.234) and in drug resistant epileptic group (CREB 0.591 ± 0.150,p-CREB 1.077 ± 0.400).The difference among the three groups had statistical significance (F =24.206,20.376,both P ＜ 0.01).Conclusions The expressions of CREB and p-CREB were significantly increased in drug resistant epileptic rats.These findings indicate that the expressions of CREB and p-CREB may play certain roles in the drugresistant epileptogenesis.
RESUMO
OBJECTIVE To investigate the antidepressant effect of triptolide in chronically unpredictable stressed mice and its possible protective effect on brain derived neurotrophic factor(BDNF). METHODS One method was selected from 8 different stress methods each day,and the mice were treated with triptolide(20,40,80 and 160μg·kg-1)10 min before the stress method. A chroni?cally unpredictable stressed model was established and after 14 d stress experiment, the total distance in the locomotor activity and the immobility time in the force swimming test and tail test were observed respectively. Triptolide(20,40,80 and 160μg·kg-1)was given 10 min before the test. In addition, Western blot was used to analyze the expression of phosphorylated cAMP response element binding protein(p-CREB) and BDNF in the hippocampus and frontal cortex. RESULTS There was no effect on the locomotor activity in any group. Compared with the normal control group,the chronically unpre?dictable stressed group showed obvious depressive-like behavior,while the immobility time in the force swimming test decreased from(161 ± 18)s in chronically stressed group to(102 ± 14)s(P<0.05) and(83±14)s(P<0.01)when mice were ip given triptolide 80 and 160μg·kg-1, respectively,and(77± 11)s(P<0.01)in imipramine(IMI)hydrochloride group(10 mg?kg-1),and(96±9)s(P<0.01)in fluox?etine(FLU)group(10 mg?kg-1). The immobility time in the tail suspension test decreased from(128± 8)s in chronically stressed group to(93±9)s(P<0.05),(85±8)s(P<0.01)and(77±11)s(P<0.01)when mice were ip given triptolide 40,80 and 160μg · kg-1 respectively,and(64 ± 9)s(P<0.01)in IMI hydro?chloride 10 mg?kg-1 group,and(72±6)s(P<0.01)in FLU group(10 mg?kg-1). Moreover,the expression of p-CREB in the hippocampus and frontal cortex significantly increased in triptolide 80 and 160μg·kg-1 groups(P<0.05),so did the expression of BDNF in the hippocampus and frontal cortex in triptolide 80 and 160μg·kg-1 groups(P<0.05). CONCLUSION Triptolide can ameliorate the depressive-like behavior in chronically unpredictable stressed mice,which may be related to the cAMP-CREB-BDNF signal transduction cascades.