The Study On Change Of Somatosensory Evoked Potentials And The Mechanisms Of Cerebral Edema After Experimental Intracerebral Hemorrhage In Rats

l.to establish the model of intracerebral internal capsule hemorrhage in rats .2.to evaluate the model of intracerebral internal capsule hemorrhage in rats .3.to explore the development and mechanisms of intracerebral edema during the different periods after experimental intracerebral hemorrhage (ICH) in rats. Methods1 .In light of the stereotactic method, the rats were positioned in a stereotactic frame, and a cranial burr hole (1.0mm) was drilled in the skull(0.1-0.2mm anterior ,3.0mm lateral to the bregma ,6.0-6.5mm ventral). l00ul autologous blood was infused into the right internal capsule area at a rate of 10 uL/min through a 9-gauge needle, Controls for needle insertion received the same quantity of saline. After intracerebral infusion, the needle was stayed for five minutes, removed, and the skin incision was closed. Then the rat model of ICH was completed.2.Regional cerebral morphology, nervous symptoms, Somatosensory Evoked Potentials , brain water content were measured .3.SPSS10.0 were used. The total significant differences of Somatosensory Evoked Potentials and brain water content during different periods were compared by one way ANOVA, Somatosensory Evoked Potentials between pre- and post- operation were compared by paired-samples T test. Results1 The lesion of experimental group was severe than that of the sham group which is irregular or ellipsoidal blood clot, different sizes, rarefaction, edema on the tissue of perihematoma, Which maybe be absorbed during different periods of ICH.2 The animals of experimental group turned into the hemiplegia and the nervous symptoms were more severe than that of sham operating group , The nerurologic grades were all more than two points. Algaesthesis of limb on contralateral side of the operation was lower than that of the operating side, and the contralateral limbs can't extend completely, some rats turn direction, dumpage to contralateral side, and can't walk, even loss of consciousness.3 All the latency of SEP(N1 , PI, Nl ?PI) of experimental group of post-operation were longer than that of pre-operation (P<0.05), But the difference of latency of sham group pre- and post-operation was not significant(P>0.05). Compared with the sham group, the difference of latency during different period (6h, 12h, Id, 5d) was significant (p<0.05), the latency of SEP during the period (2d, 3d)were prolonged significantly(P<0.01), but the difference of the latency of SEP of the group of 7d was not significant (p>0.05).4 Compared with sham group, the difference of the brain water content on the side of operation of the group of ( 6h, 12h, Id, 4d, 5d ) was significant (p<0.05), 2d, 3d (p<0.01) , but the difference of the brain water content of group of 7d was not significant(p>0.05). However, the difference of the brain water content on the contralateral side of the operation of the group (2d , 3d) were significant. 2d(p<0.05), 3d(p<0.01).Conclusions1 We can copy the model of intracerebral internal capsule hemorrhage in rats by means of stereotactic method successfully.2 Somatosensory Evoked Potentials (SEP) is the best objective index to evaluate the model of intracerebral internal capsule hemorrhage in rats.3 The development of intracerebral edema after ICH is consecutive course. As long as we explore the mechanisms of cerebral edema during different periods of7ICH, we can provide the therapy for ICH with correct guidance.