Application And Evaluation Of Skull Perforation In A Rat Model Of SSST

Objective：Observe and evaluate skull perforation method in the application of SSST rat modelcompared with other two methods through determining the expression of brain protein andcaspase3in the CNS, so as to explore a successful stable SSST rat model that is easy tocopy and have light injury, thus to provide a new experimental model for subsequentresearch.Methods:63healthy adult male SD rats were divided into three groups (group A, B and C, n=21)in random. Group A: The rats of post-craniotomy were injected with ActivatedCephaloplastin Reagent in the posterior1/3SSS (n=18). Group B: The rats ofpost-craniotomy were Ligated the posterior1/3SSS and bridging vein, then injected withActivated Cephaloplastin Reagent. Group C: The rats were drilled merely the posterior1/3SSS and injected with Activated Cephaloplastin Reagent. All groups were divided againinto three subgroups:8h (A1, B1, C1, n=7),24h(A2, B2, C2, n=7),72h(A3, B3, C3, n=7).The changes of neurological function classification were detected at different time pointand cell morphological characters were observed by using Nissl’s staining and HE staining.Expressions of neuroglobin and caspase-3were tested by immunohistochemistry.Results:1. Neurological deficit: The neurological function at different time points of eachgroup was analyzed by a one-way analysis of variance, and it had statistical significanceamong these subgroups (P=0.001, F=10.520),(P=0.000, F=12.229),(P=0.001, F=11.641).Neurological deficits in the three models were time-dependently increased. It hadsignificant difference among the subgroups in each group. Group A and B and Group Band C were both different from each other in statistics, however, there was no statisticalsignificance compared group C with A (P>0.05). Neurological deficit in group B are most serious.2. Cerebral water content: The cerebral water content at each time point of the threegroups was analyzed by a one-way analysis of variance, and it had statistical differenceamong these subgroups (P=0.003, F=8.425),(P=0.000, F=16.740),(P=0.00, F=9.129).Parasagittal water content at8h of post-craniotomy was increased. The increase was moreobvious at24h and achieved peak at72h, leading to cerebral edema. Cerebral watercontent had significant difference among the subgroups in each group. Group A and B aswell as Group B and C were both different from each other in statistics except that nostatistical significance was shown between group A and C (P>0.05). Group B had the mostcerebral water content.3. HE staining: At8h and24h, we found that cerebral edema and degeneration ofneuron were both obvious, and it displayed karyopycnosis, extensions vanished, enlargedvascular space and vasodilatation. At72h, neuron was rarefaction, cellular spaces wereaccreted, a lot of degenerated and necrotic neurons were existed and more exudation oferythrocyte was observed.4. Nissl’s staining: There exist dark-blue solids or plaque corpusule of Niss (tigroidappearance). The numbers of Nissl were decreased from8h to72h. Background appearedlight-blue and nucleus was blue.5. Immunohistochemistry of caspase-3: The difference in each subgroup of group A,B and C was separately analyzed by a one-way analysis of variance, and it all hadstatistical significance among the subgroups (P=0.000，F=164.671),(P=0.000，F=34.760),(P=0.000，F=71.523). We found that positive cells of caspase-3were increased at8h,achieved peak at24h but were reduced slowly at72h. It should be noted that positive cellsof caspase-3at72h were more than at8h. The expression of neuroglobin had statisticalsignificance among different subgroups. Group A and B as well as Group B and C wereboth different from each other in statistics, but no statistical difference was shown betweengroup A and C (P>0.05). Group B had most positive cells of caspase-3.6. Immunohistochemistry of neuroglobin: The expression of neuroglobin at each timepoint of the three groups was analyzed by a one-way analysis of variance, and it had statistical difference among these subgroups (P=0.003，F=8.418),(P=0.000，F=13.689),(P=0.000，F=22.033). It was shown that the expression of neuroglobin and positive cells ofneuroglobin were decreased in a time-dependent manner. It had significant difference inthe expression of neuroglobin among different subgroups. Group A and B as well as GroupB and C were both different from each other in statistics, however, the expression ofneuroglobin had no statistical difference between group A and C (P>0.05).Conclusion:1.Skull perforation method can be used to build SSST rat model.2.Building SSST rat model by skull perforation can provide an experimental modelthat is easy to copy for studying pathogenesis and pathophysiological evolution ofcerebral venous sinus thrombosis.