Carbenoxolone pretreatment and treatment of posttraumatic epilepsy

Gap junction blocking agents can inhibit spontaneous discharge frequency in cells. We established a rat model of posttraumatic epilepsy induced using ferric ions. Rats were intraperitoneally injected with carbenoxolone, 20 mg/kg, prior to and 30 minutes after model establishment, once a day for 14 consecutive days. Immunohistochemistry showed glial cell proliferation around a cortical focus and significantly increased connexin expression in posttraumatic epilepsy. However, carbenoxolone pretreatment or treatment significantly reduced connexin expression in the cortex, inhibited glial fibdllary acidic protein expression and ameliorated seizure degree in rats. These findings indicate that large amounts of glial cell proliferation and abnormal gap junction generation play a role in posttraumatic epilepsy, and that carbenoxolone may prevent and treat this disease.

Pial iontophoresis of ferric chloride versus cortical ferric chloride injection in establishing iron-induced posttraumatic epilepsy animal models

BACKGROUND： In order to study the pathogenesis of iron-induced posttraumatic epilepsy （PTE）, foreign scholars have established several kinds of PTE animal models, among which, the iron- induced PTE animal models proposed by Willmore is the most famous. The iron-induced PTE animal models can be established by two methods： one is cortical ferric chloride injection （CFCI） and the other one is pial iontophoresis of ferric chloride （PIFC）. Because Willmore did not give out the elaboration of the behaviors and electroencephalograms （EEGs） of the iron induced PTE animal models established by these two methods, so we have known little about these animal models. OBJECTIVE： To observe the behaviors and EEGs of the iron-induced PTE animal models established by PIFC and CFCI, in order to compare the differences and the study value of these two methods. DESIGN： Qualitative controlled observation tria SETTING： Department of Neurosurgery, Urumqi General Hospital, Lanzhou Military Area Command of Chinese PLA. MATERIALS： Forty healthy adult male SD rats, weighing 200 to 250 g, were involved in this experiment. Reagents and instruments： Ferric chloride （FeCl3·6H2O, Sigma USA）, rat stereotaxic apparatus （ASI company, USA）, the wireless blue tooth electroencephlograms recording system （Nuocheng electric Co.Ltd, Shanghai）, a set of air turbine dental drill unit, dental base acrylic resin powder, microinjector （50 μL）, amperemeter （1 mA）, a pair of batteries, electric resistance （200 kΩ） , variable resistance （100 kΩ）, tubule with endo-meridians of 2 mm （used as import tube）, several silver wire segments and several acupuncture needles were employed in this study. METHODS： This study was carried out in the Experimental Animal Center of the Urumqi General Hospital, Lanzhou Military Area Command of Chinese PLA between November 2004 and April 2005. Establishing the PET animal models by CFCI method： Twenty SD rats were taken, intraperitoneally anesthetized with 50 mg/kg barbanylum and fixed on stereotaxic apparatus. A cranial burr hole with the diameter of 2 mm was drilled 3 mm behind the coronal suture and 2 mm lateral to the sagittal line on the left cranium. Another 5 cranial burr holes with diameter of 2 mm were drilled to place electrodes. The positions of holes were set that taking bregma as original point, sagittal line as Y-axis, the line through the original point and vertical to the Y-axis as X-axis. The unit of the coordinate axis was mm. The coordinate value of the electrodes were （4, 0）, （4, -6）, （-4, 0）, （-4, -6）, at last, a hole with the diameter of 2 mm was drilled on the center of the coronale. 5 μL ferric chloride solution （FeCl3, 100 mmol/L, pH 1.5） was injected into the sensorimotor cortex of rats using microinjector within 5 minutes. The needling depth was 3 mm. The needle was retained for 5 minutes so as to prevent the outflow of liquid. Establishing the PTE animal models by PIFC method： Twenty SD rats were chosen and weighed, and the procedures after weighing were as above.A cranial burr hole with the diameter of 4 mm was drilled in the position where needle inserted in animal models established by CFCI method. Cerebral dura mater was cut. Another 5 holes were drilled to place electrodes in the same position as above. The tip of tubule cotton stuffed inside （to prevent the rapid flow of FeCl3 solution, 100 mmol/L, pH 1.5） was gently connected to cerebral pia mater. The positive and negative electrodes of the amperemeter whose output current was 100 μA were connected to acupuncture needles. The acupuncture needle, which was connected to positive electrode, was inserted into ferric chloride solution, and that which was connected to negative electrode was inserted into the right forelimb of rats subcutaneously. The rats were galvanized for 10 minutes. Record of EEG： The silver wire with blunt anterior extremity was placed on the cerebral dura mater. Then, silver wire and cranial bones were firmly fixed with dental base acrylic resin power. The other side was connected to the wireless blue tooth electroencephlograms recording system to monitor EEG changes. Assessment criteria of seizure degree： Grade Ⅰ ： ＂wet dog-like＂ shudder, facial muscle convulsion and chewing;Grade Ⅱ： rhythmical nodding：Grade Ⅲ： forelimb clonus：Grade Ⅳ： forelimb clonus while standing： Grade Ⅴ： lost the balance, vert, limb＇s convulsion and the whole body＇s tic. MAIN OUTCOME MEASURES： Behaviors and EEGs changes of iron-induced PTE animal models established by PTFC and CFCI. RESULTS： All the 40 rats were involved in the result analysis. （1） The changes of the behaviors： The two animal models both had the epileptic seizures. The epileptic seizure of the animal model established by PIFC mainly presented automatic behavior of chewing, and facial muscle convulsion accompanied with chewing. Epileptic seizure reached the peak within 2.5 to 7 hours after model establishing.It was gradually decreased within 24 hours and hardly seen 1 day after model establishing. The epileptic seizure of the rat model established by CFCI mainly presented turnover upspring and limbs＇ convulsion and urinary incontinence accompanied. The epileptic seizure reached the peak within 3 to 8 hours.It was relatively frequent within 1 week and gradually decreased within 2 weeks after model establishing. The PTE animal models established by CFCI were more closed to clinical PTE process. （2） The form of seizures： The epileptic seizures of the rat model established by PIFC mainly presented grade Ⅰ , seldom presented grades Ⅲ, Ⅳ and Ⅴ; The epileptic seizures of rat model established by CFCI mainly presented the head turning to the right, body＇s rotation, then appeared as grades Ⅳ and Ⅴ, and the whole procedure lasted 1 minute. At the interval of big seizures, grade Ⅰ was observed. From the respect of seizure manifestation, the PTE models established by CFCI were more similar to human PTE. （3） EEGs changes： The sharp waves with average frequency of 9.66 Hz and average amplitude of 183.90 μV were observed on the EEGs of the model established by PIFC when the rats were suffering seizures. The spike waves with average frequency of 16.01 Hz and average amplitude of 143.60 μV were observed on the EEGs of the model established by CFCI when the rats were suffering seizures. CONCLUSTON： （1）Iron-induced PTE rat model is stable and credible. （2）Compared with PTE animal model established by PIFC, PTE animal model established by CFCI is a chronic animal model, and its seizure manifestation is more similar to human PTE. so it is worth further studies.

Clinical Research and Surgical Treatment of Posttraumatic Epilepsy

In order to investigate the susceptible factors of posttraumatic epilepsy (PTE) and the surgical treatment, the relative factors of 18 cases of intractable PTE and 35 cases of non-PTE patients with posttraumatic seizures (PTS) and the surgical treatment of PTE patients were studied retrospectively. The results showed that there was significant difference in the degree of unconsciousness after head injury, incidence of intracerebral hematoma and acute subdural hematoma between PTE group and non-PTE group. Of the 18 cases of PTE undergoing surgical treatment, the effectiveness of 11 cases was satisfactory and that of the remaining 7 was not. Between the two groups, there was difference in the localization of interictal epileptic discharge (IED) and ictal discharge (ID) as demonstrated by preoperative EEG. It was concluded that PTE was associated with the severity of head injury and intracranial hematoma. The localization of epileptogenic loci by preoperative EEG presumably contributed to the PTE surgical effects.

Neural stem cell activation and glial proliferation in the hippocampal CA3 region of posttraumatic epileptic rats

The present study observed the dynamic expression of CD133, nuclear factor-κB and glial fibrUlary acidic protein in the hippocampal CA3 area of the experimental posttraumatic epilepsy rats to investigate whether gliosis occurs after posttraumatic epilepsy. CD133 and nuclear factor-κB expression was increased at 1 day after posttraumatic epilepsy, peaked at 7 days, and gradually decreased up to 14 days, as seen by double-irnmunohistochemical staining. Glial fibrillary acidic protein/nuclear factor-EB double-labeled cells increased with time and peaked at 14 days after posttraumatic epilepsy. Results show that activation of hippocampal neural stem cells and glial proliferation after posttraumatic epilepsy-induced oxidative stress increases hippocampal glial cell density.