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Objective: Epilepsy is the brain neurons excessive abnormal discharge resulting in recurrent and transient central nervous system dysfunction characterized by a brain function disorders syndrome, its pathogenesis remains unclear. Epilepsy can cause brain damage, apoptosis, or programmed cell death, a series of complex protease cascade is epileptic brain injury caused by an important way. Epilepsy repeatedly for a long time after the onset of brain selective neuronal apoptosis necrosis and hippocampal sclerosis, once the hippocampal sclerosis, brain tissue damage will be irreversible and memory dysfunction. The pentylenetetrazol (pentylenetrazol and PTZ) by intraperitoneal injection of status epilepticus rat model to observe the morphological changes of the hippocampus, such as the use of Nissl staining method to detect the loss of nerve cells necrosis; Timm staining hippocampus mossy fiber sprouting situation; electron microscopy ultrastructure of hippocampal CA3; using immunohistochemical method to calculate the mean optical density of positive cells; Western blot method were detected the hippocampus caspase3 and hsp70 expression. Discussed seizures caspase3-mediated apoptosis pathway and Hsp70 dynamic expression, will contribute to the molecular level to seek more effective therapeutic target for epilepsy, timely intervention and control the occurrence of apoptosis, as The alleviate epilepsy brain injury caused by a new method. Method: select the cleaning level (SPF grade) male Sprague-Dawley (SD) rats 70, the experimental starting weight (180 ± 20) g, 12h light / dark conditions 22 ° C -25 ° C environmental temperature, cage feeding. The experimental animals were randomly divided into status epilepticus group (status epilepticus, SE group) and control group (normal Control group, two groups of NC group), SE group was divided into seizures after 3h, 6h, 12h group, 24h , 5 groups of 14 each. SE application of saline solution in rats 1% PTZ solution, first by 40 mg / kg intraperitoneal injection to 20 mg / kg, 10 min after the onset of experimental animals amount of an additional 10 mg / kg, until the emergence of level IV or V, attack. Racine will ignite divided into six evaluation criteria, is still widely used in the experiment. 0, no reaction: the level Ⅰ wet dog shakes, facial twitching and chewing; class II, neck muscle spasms, showed nod and / or drift; Ⅲ level, the side of the forelimb spasm; Ⅳ level, bilateral forelimb spasms associated with standing; Ⅴ level, body clonus, loss of balance or even fall. The fully lighted standards reached level IV or V, attack and continued for 30 minutes or more. The control group was injected with an equal volume of saline. Observe the behavior of rats changed after the rats in each group were randomly selected three lines of Nissl staining and Timm staining were detected in hippocampus nerve cells lost necrosis and mossy fiber sprouting, 3 for electron microscopy hippocampal CA3 super microstructure, five rows immunohistochemical method to calculate the mean optical density of positive cells, 3 for Western blot, respectively the detection hippocampus caspase3 and hsp70 expression. The sustained tonic seizures and convulsions of death in the course of the experiment rats should be timely supplement (supplement 28). Results: The preparation of animal model SE group effective application of the 70 rats, 11 applications of 40 mg / kg, 14-50mg / kg, 15-60mg / kg, 18-70mg / kg, 8 80mg / kg, 4 PCS 90mg / kg PTZ begins convulsions, mainly for rhythmic nodding, myoclonus. With PTZ every 10 min injection time soon twitching limbs into generalized tonic seizures result in a loss of postural control, front and hind legs strong contraction, accompanied by respiratory depression, perioral purple varying duration. The tonic stage after generalized tonic - clonic seizures. NC group animals had no behavioral changes. The rat hippocampus histological changes 2.1 Nissl staining SE were observed in neurons shrinkage smaller, deeply stained nuclei, nuclear fission and nuclear dissolved, with the characteristics of apoptosis, the majority of cytoplasmic vacuolization, hippocampal CA1 neurons arranged scattered, cell density, reduced Nissl bodies, some neuronal loss, 24h group most obvious, 3h brain damage lightest; control group hippocampal neurons form the structural integrity of the nuclei lightly stained, clear cytoplasm, the cells of the CA1 area was almost uniform purple, blue, cell density the Nissl blue, shape near normal. 2.2 Timm staining was used to observe the CA3 region of SE Asian group and control group mossy fiber sprouting score only 0-1. 2.3 hippocampal CA3 ultrastructural observation of the SE group hippocampal CA3 visible neurons nuclear membrane ill-defined, retraction, chromatin set of edges, reduce the number of mitochondria or swelling, 24h group is the most obvious, 3h group lighter; clear nuclear membrane of neurons in the control group, mitochondrial integrity, largely intact organelles. 3 brain tissue caspase3 and hsp70 expression SE of 3h caspase3 and hsp70 in the cytoplasm of nerve cells in the hippocampus coloring began to increase, the rate of positive cells (P lt; 0.01 compared with the control group), and with time the rate of positive cells consequential in nature. increased, 24h was significantly higher (P lt; 0.01). Control group to be seen caspase3 and hsp70 present in the hippocampus cytoplasm scattered coloring. Of 4 rat hippocampus caspase3 and hsp70 protein expression SE of 3h caspase3 and hsp70 expression began higher (P lt; 0.05 compared with the control group), 24h was significantly higher (P lt; 0.05). Control group, only a small amount of caspase3 and hsp70 expression. Conclusion: an intraperitoneal injection pentetrazole may successfully induced status epilepticus in rats, is an ideal animal model of analog generalized tonic - clonic seizures. 2 seizures acute phase caused varying degrees of morphological changes of the brain tissue, but the attack within 24h does not appear significant mossy fiber sprouting change, indicating no significant obstacles in memory function in rats, this period can be reversed if timely termination of seizures brain damage. 3 seizures can lead to nerve cell apoptosis may increase expression of caspase3 and hsp70 brain tissue stress plays an important protective role.
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