| Objective Most epilepsy patients can alleviate after drug treatment. But, about 20% of patients with epilepsy is invalid in drug treatment and then becomes intractable epilepsy. Temporal lobe epilepsy(TLE) is the most prevalent form of intractable epilepsy. The strategy of new targeted drug therapy and surgery is a new hope for such patients, which it has been shown that the surgery have a good outcome. Whether new drugs targeting therapy or surgery treatment, the key to its success depend on the location of epileptogenic focus caused by responsibility lesions which will influence the outcome. But there is no a kind of examination method that can accurately specific to detect epileptogenic zone of all the epilepsy. Recently, the preoperative evaluation including MRI, v EEG, PET-CT and neural electro--physiological comprehensively locate the epileptogenic zone. Among these, MRI was widespreadly used for preoperative evaluation because of its advantages. However, the conventional MRI are not specific. With the deep research of the molecular MRI technology and wide preparation of MNPs, we are expected to find a kind of convenient and noninvasive method to target the epileptogenic zone of intractable temporal lobe epilepsy based on MRI. This experiment being at the molecular level used a new kind of SPIONs with low toxicity and superparamagnetic properties, which chelating an no radioactive AMT molecules on the surface, to explore the functional nano probe whether can through the BBB or reach and then targeted locate the epileptogenic zone of temporal lobe epilepsy base on molecular MRI and discuss the optimal scan time of MRI and its side effects on the brain.Method In this study, a rodent model of TLE was prepared by injecting lithium chloride-pilocarpine. And the experiment is divided into two parts. The first part: the targeted probe was synthesized by covalently attaching nonradioactive AMT to SPIONs composed of iron oxide and dextran. P-SPIONs that no surface modified and no targeted and the saline served as the control materials. AMT-SPIONs, P-SPIONs and the saline were injected respectively into the models of TLE through the tail-vein during the acute stage 72 h after status epilepticus. MRIs were obtained before and after particles injection in all animals, and then The T2 value and singal of the epileptogenictissue measured and compared. To decollate and take the brain tissue freezing section after MRI. Perl's iron stain was performed for the specimen of the brain to discuss whether the nanoparticles crossing the BBB or not. Nissl stain and FJB stain were performed for the specimen of the brain to observe the damage of the hippocampal neurons, and to investigate whether the nanoparticles are sufficiently toxic to the brain cells or not. The second part: AMT–SPIONs was respectively injected into the models of temporal lobe epilepsy through the tail vein during the acute stage 72h/8w after SE. MRI were obtained before and 60min?120min?240min?480min?24h after particles injection in all animals, and then measured the T2 value of the epileptogenic tissue.Result 1. The rat of epilepsy model induced by Lithium chloride-pilocarpine was characterized by the typical status epilepticus of human temporal lobe epilepsy. Rats being in the waking state showed slobbering and bloodshot in eyes after the injection of pilocarpine about 30 min. The first part: the success rate of epilepsy model was 90%. In accordance with the principle of random, the modes were divided into three groups:saline control group(n=15), P-SPIONs control group(n=15), the AMT--SPIONs experimental group(n=15). The second part: the success rate of epilepsy model was 86%, 12 epileptic rats were selected randomly in acute stage experiments, which the rest of the model rats were monitoring in video monitor to induce the chronic phase model. Epilepsy model rats should added timely based on the principles of random in each group if the rats died. 2. T2 value of epileptogenic zone before the injection of medicine have no significant difference(P>0.05) between three groups. There was no significant difference(P>0.05) compared pre-injection with post-injection in T2 signal of the saline group and P-MNPs group. Compared with The T2 value before the injection, the T2 signals of lesions local tissue of acute and chronic models of temporal lobe epilepsy had a negative increased change(P<0.01). The T2 value of all time points in acute stage decreased respectively by 3.79%, 6.25%, 14.71%, 9.96%, 14.71% of the before injection. And the The T2 value of all time points in chronic stage decreased respectively by 3.86%, 8.32%, 14.20%, 12.79%, 14.20% of the before injection. The T2 value had the greatest reduction when 240 min after the injection, and during acute and chronic phase. 3. Prussianblue staining showed that the brain tissue of AMT-SPIONs group(P<0.01) and P-SPIONs group(P<0.05) have iron particle distribution compared with the saline group. 4.The three group have no statistical significance(P>0.05) in number and form of the neuron and FJB positive neurons in hippocampus CA3.Conclusion 1. AMT-MNPs and P-MNPs can cross the BBB. 2. Contrast AMT-MNPs and P-MNPs, AMT-MNPs have a stranger ability of combining with the epileptogenic tissues on MRI. And the optimal scan time of imaging is 240 min after the injection of AMT-SPIONs. 3. histopathology result suggest that these particals won't injury the brain cells. 4. The study suggest that the targeted nanoparticles have a good development prospect in localization and diagnosis of epilepsy. |
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