Propagation of brain injuries from artificial focus into the opposite hemisphere at the early stage of rat electrogenic epilepsy identified by histology and magnetic resonance image / 生理学报

The purpose of this work was to study the characteristics of rat brain abnormalities at two hemispheres at the early stage of electrogenic epilepsy. Experiments were performed on 37 male Sprague-Dawley rats. Chronically repetitive tetanization (60 Hz, 2 s, 0.4 - 0.6 mA) was used to stimulate the right dorsal hippocampus (DHPC) of the rat brain once a day for 2, 4, 6, 8 or 10 d, respectively. The T(2) weighted magnetic resonance image (T(2)-WI) were obtained from each experimental rat at the end of the experiments. Histological sections were obtained after experimentation. The results showed that the main pathologic changes at the early stage of epilepsy included: (1) T(2)-WI hyperintensification, the histological enlargement of lateral ventricle (LV) and pathological hyperplasia of ventricular choroidea plexus occurred. The pathological hyperplasia was symmetric in two hemispheres, but the LV enlargement was not. (2) Histologically enlarged LV area showed a resemblance to T(2)-WI hyperintensive area. Compared with the control rats, large T(2)-WI hyperintensive area (P=0.0259; P=0.0184; P=0.0184; P=0.0404; P=0.0259) and histologically enlarged LV area (P=0.0210; P=0.01; P=0.0100; P=0.0152) were present in chronically tetanized rats. (3) Dynamic characteristics of histologically enlarged LV area resembled to those of T(2)-WI hyperintensity area in chronically tetanized rats at different stimulating day. Lateralization of T(2)-WI hyperintensity was in accordance with that of T(2)-WI abnormal area and of histologically enlarged LV. These abnormalities were severe on the contralateral side on the stimulating day 6, or on the ipsilateral side on the stimulating day 10. These results imply characteristic propagation of brain abnormalities crossing to the opposite hemisphere at the early stage of an electrogenic rat epilepsy.

The effects of Erigeron breviscapus preparation on the imaging and neuronal metabolites at the early time points after reperfusion following the ischemic cerebral injury in rats / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the effects of Erigeron breviscapus preparation on the imaging and neuronal metabolites after reperfusion in the ischemic cerebral injury in rats.</p><p><b>METHOD</b>Twenty-three male Sprague Dawley rats with an average body weight of (165 +/- 15) g (mean +/- S) were used, and were randomly divided into two groups: group A rats (n = 11) underwent an operation of ischemic brain injury, group B rats (n = 12) underwent the same operation and received the treatment of Erigeron breviscapus preparation (1.5 mg.kg-1 weight, i.p.). The right middle cerebral artery occlusion (MCAO) of rats in both groups was induced by 5/0 nylon suture for 2 hours. The reperfusion was conducted for four hours and six hours respectively following MCAO. T2 weighted-imaging (T2WI) and 1H-magnetic resonance spectroscopy (1H-MRS) were performed, to study the changes of the imaging and the neuronal metabolites N-acetyl aspartate (NAA), creatine/phosphocreatine (Cr/PCr), choline (Cho) and lactose (Lac) in cerebrum following cerebral ischemia.</p><p><b>RESULT</b>The hyperintense signals in the right cerebrum in group B decreased compared with those in group A, the T2 values decreased, the level of NAA increased, the ratio of Cr/NAA and Cho/NAA decreased, and no lactose was observed. The brain surface vessels of rats in group B were in the state of dilation.</p><p><b>CONCLUSION</b>Erigeron breviscapus preparation is beneficial to the reestablishment of the blood circulation in the ischemic brain, and to the improvement of the neuronal metabolism and survival.</p>

Effects of Angelica sinensis injection on the neuronal metabolites and blood flow speed within reperfusion following the ischemic cerebral injury in rats / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of Angelica sinensis injection on the neuronal metabolites and blood flow speed within reperfusion in the ischemic cerebral injury of rats.</p><p><b>METHODS</b>Sixty-nine male Sprague Dawley rats with an average body weight of 150 to 170 g were used, and were randomly divided into three groups: sham operation group (n = 4), ischemia injury group (n = 30) underwent an operation of ischemic brain injury, Angelica-treated group (n = 35) underwent the same operation and received the treatment of Angelica sinensis injection (5 g/kg bw, i. p). The right middle cerebral artery occlusion (MCAO) of both ischemia injury group and Angelica-treated group rats was induced by 5/0 nylon suture for 2 hours. The reperfusion was conducted for three to four hours and five to six hours respectively following MCAO. T2 weighted-imaging (T2WI) and 1H magnetic resonance spectroscopy (1H MRS) were performed, to study the changes in imaging and neuronal metabolites N-acetyl aspartate (NAA), creatine/phosphocreatine (Cr/ PCr) and choline (Cho) following cerebral ischemia. The changes in blood flow speed were measured by laser Doppler flowmetry. The surface vascular density in right hemisphere were calculated.</p><p><b>RESULTS</b>The hyperintense signals and volume in the right cerebrum in Angelica-treated group decreased compared with those of the ischemia injury group, the T2 values were decreased, and the level of NAA increased, the ratio of Cr/NAA and Cho/NAA decreased. The blood flow speed in Angelica-treated group was improved. The length of brain surface vessels in group C increased.</p><p><b>CONCLUSION</b>The Angelica sinensis injection enhanced the blood circulation in the ischemic brain, improved the neuronal metabolisms.</p>

Development and progression in rat brain abnormalities related to early stage of epilepsy measured by magnetic resonance image / 生理学报

The purpose of the present study was to investigate the features of pathophysiological neural networks in rat temporal lobe epileptogenesis. To establish electrogenic epilepsy model, repetitive tetanization (60 Hz, 2 s, 0.4-0.6 mA) was delivered into the right dorsal hippocampus (HPC) of rat brain. Rats were divided into different groups. Experimental animals received tetanic stimulation once a day for 2, 4, 6, 8 or 10 days, respectively. Primary wet dog shakes (WEDS) of the animals were recorded daily during the stimulation to understand the development of behavioral seizures at early stage of epilepsy. The T(2)-weighted (T(2)-WI) spin-echo images were obtained from each experimental rat. The results demonstrated that T(2)-WI hyperintensity of experimental rats was observed in bilateral symmetric dorsal lateral ventricle (LV) areas at stimulating day 2 (n=4), in contralateral medial and ventral LV areas to the side of the electrode at stimulating day 6 (n=5), in contralateral ventral LV areas at stimulating day 8 (n=3), and in ipsilateral ventral LV areas at stimulating day 10 (n=4). Therefore the peak rate of primary WEDS appeared on stimulating day 4 in the experimental rats. Morphological identification demonstrated that the T(2)-WI signal abnormalities were related to the enlarged LV and pathological ventricular choroidea plexus hyperplasia. The results suggest that the development of rat brain abnormalities from dorsal LV to ventral LV at early stage of epilepsy can be measured by magnetic resonance image, which implies reorganization of pathophysiologically functional networks before kindling effect appear.