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 trial.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 andⅤ, and the whole procedure lasted 1 minute. At the interval of big seizures, gradeⅠwas 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.CONCLUSION: ①Iron-induced PTE rat model is stable and credible. ②Compared 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. 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 the differences and the study value of these two methods. DESIGN: Qualitative controlled observation trial. SETTING: Department of Neurosurgery, Urumqi General Hospital, Lanzhou Military Area Command of Chin 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 (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 fixe d onstereotaxic 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 The needle was retained for 5 minutes so as to prevent the corneale. 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 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 animal models established by CFCI method. Cerebral dura mater was cut. Another 5 holes were drilled to place electrodes in the same position as 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 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 acupuncture needle, which was connected to positive electrode, was inserted into ferric chloride solution, and that was was connected to negative electrode was inserted into the right forelimb of rats subcutaneously. of EEG: The silver wire with blunt anterior extremity was placed on the cerebral dura mater. Then, silver wire and cranial bones were fixed 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, limbs convulsion and the whole body’s tic. MAIN OUTCOME MEASURES: Behaviors and EEGs changes in iron-induced PTE animal models established by PTFC and the 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 established. It was gradually decreased within 24 hours and hardly seen after 1 day after model established. The epileptic seizure of the rat model established by CFCI is mainly presented in 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 established. 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 Ⅰwas observed. seizure manifestation, the PTE models established by CFCI were more similar to human PTE. ③ EEGs changes: The sharp waves with average frequency o f 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 the average amplitude of 143.60 μV were observed on the EEGs of the model established by CFCI when the rats were suffering seizures.CONCLUSION: Iron-induced PTE rat model is stable and credible. ②Compared 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.