| Objective:1.To establish a stable and reliable animal model of cerebral ischemia after subarachnoid hemorrhage(SAH)in SD rats.2.To verify the therapeutic effect of cSCS in this animal model.Methods:1.300-350 g male SD rats were used as experimental animals and randomly divided into experimental group and control group,with 8 rats in each group.After 10% chloral hydrate anesthesia was satisfactory,a miniature electric drill was used to drill a 2mm hole in the skull at 6mm on the lateral side of the coronal sagittal point and 1mm on the posterior side.The changes of cerebral blood flow in the cerebral cortex of SD rats were monitored in real time by laser doppler(LD)and the blood flow change curve was recorded.One day later,these rats were anesthetized with 10% chloral hydrate again.Keeping the head down 30°,the central part of the posterior occipital was cut open and the annular occipital fascia was exposed,and cerebrospinal fluid(0.2ml)was extracted by occipital cistern puncture.Autologous femoral arterial blood was injected into the occipital cistern at a rate of 0.1ml/min,and the injection hole was closed with bone lamella.Keeping the head low status for 20 min to make the blood distribute in the subarachnoid space.The second blood injection which repeated the first operation and injected 0.2ml blood again was carried out after 48 hours.SD rats in control group were injected with normal saline instead of autologous blood into occipital cistern using the same method.Five days after the second blood injection,the changes of cerebral blood flow in the SD rats were monitored by laser doppler(LD)in real time,and the blood flow curve was also recorded.The experimental data of cerebral blood flow were expressed as mean ± standard deviation,and the differences between groups were compared by one-way anova.The data were analyzed by GraphPad Prism7.04 statistical software.P< 0.05 indicated a significant difference.2.After successful modeling,the SD rats were randomly divided into three groups with 8rats in each group.Laser doppler(LD)was used to monitor the cortical cerebral blood flow(CBF)as baseline in each subarachnoid hemorrhage(SAH)rat model The first group was blank control group without any treatment.The second group was false stimulation group where micro electrical stimulation electrodes were implanted in the rat C1 and C2 vertebra after 10% chloral hydrate anesthesia with the power off.The third group was stimulating group where micro electrical stimulation electrodes were implanted in the rat C1 and C2 vertebra after 10% chloral hydrate anesthesia with the power on.The second group and the third group were implanted with spinal stimulation electrode immediately after modeling.The cortical CBF of each rat was monitored by laser doppler(LD)on day3,5 and 7 after the operation.The CBF curve was recorded and the rate of CBF change was calculated according to the baseline.The experimental data of cerebral blood loss rate were expressed as mean ± standard deviation.The data were analyzed by GraphPad Prism7.04 statistical software.P< 0.05 indicated a significant difference.Results:1.During the establishment of an animal model of subarachnoid hemorrhage,the mortality rates of the experimental group and the control group were 25% and 12.5%,respectively.On the fifth day after the operation,the cortical CBF of SD rats in the experimental group and the control group was 191.58±5.11 pu and 372.54±9.26 pu,respectively.Compared with the control group,the cortical CBF of SD rats in the experimental group decreased significantly.2.On the 3rd,5th and 7th day after the operation,the changes of CBF in the temporal cortex of SD rats in stimulation group were 0.2451±0.06436,0.0225±0.05364,and-0.0482±0.04437,respectively,and those in the false stimulation group were-0.1476±0.01755,-0.2962±0.01761,and-0.3540±0.01476.The blank control group was-0.1543±0.01502,-0.2989±0.01301,and-0.3593±0.01957(P<0.05).Conclusion:1.The SD rats can simulate the cerebral ischemia after subarachnoid hemorrhage by the method of secondary injection of blood into the occipital cistern.2.Cervical spinal cord electrical stimulation(CSCs)can slow down the decline of cerebral ischemia after SAH. |
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