Sherdil Ariana, Chabardès Stéphan, Guillemain Isabelle, Michallat Sandrine, Prabhu Shivadatta, Pernet-Gallay Karine, David Olivier, Piallat Brigitte
Inserm, U1216, Grenoble, F-38000, France; Univ Grenoble Alpes, Grenoble, F-38000, France.
Inserm, U1216, Grenoble, F-38000, France; Univ Grenoble Alpes, Grenoble, F-38000, France; CHU Grenoble Alpes, Service de Neurochirurgie, Pôle PALCROS, Grenoble, F-38000, France; Clinatec, Centre de recherche Edmond Safra, CEA-LETI, Grenoble, F-38000, France.
Epilepsy Res. 2018 May;142:20-28. doi: 10.1016/j.eplepsyres.2018.03.008. Epub 2018 Mar 9.
Our objective was to propose a new on demand non-human primate model of mesial temporal lobe seizures suitable for pre-clinical innovative therapeutic research.
Five macaques were stereotaxically implanted unilaterally with a deep recording electrode in the hippocampus. For each experiment, penicillin was injected into the hippocampus and animals were monitored during five consecutive hours. A total of 12-27 experiments with a mean cumulative dose of 162644 ± 70190 UI of penicillin have been performed per animal Injections were repeated at least once a week over a period of 98-276 days. The time-course of electro-clinical seizures and the response to diazepam have been quantified from, respectively, 84 and 11 experiments randomly selected. To evaluate brain injury produced by several penicillin injections and to characterize the changes occurring into the hippocampus, we performed an histological analysis, including neuronal nuclei and glial fibrillary acid protein immunostaining and electron microscopy.
After each penicillin injection, we observed that the electro-clinical characteristics were reproducible among non-human primates and experiments. Seizures duration was stable (29.60 ± 6.62 s) and the frequency of seizures reached a plateau with about 3 seizures/20 min during 180 min and that could be useful to test new treatments. Diazepam did not modify the course of the seizures. Hippocampal sclerosis was found similar to that encountered in epileptic patients with a neuronal loss and a glial cells proliferation. Electron microscopy analysis of CA1 revealed a decreased number of synapses and a large amount of glial fibrillary filaments in the injected hippocampus. Interestingly, this on-demand model of seizure, turned into a chronic model with spontaneous occurrence of seizures after a cumulative amount ranging from 119 to 145 KIU of penicillin injected.
The present study shows that an on-demand model of mesial temporal lobe seizure can be developed by intra-hippocampal injection of penicillin. The seizures are reproducible, stable and resistant to diazepam. Brain damages are confined to the hippocampus with similar features to that found in human mesial temporal lobe epilepsy. This model reproduces the symptomatogenic and the irritative zone usually seen in human MTLE, with the additional advantage of having a clear delineation of the epileptogenic zone. However, the mechanism of actions of the penicillin as a proconvulsant agent does not replicate all of the much more complex physiological and cellular mechanisms that are involved in human epilepsy and represent a limitation of our study that one must be aware of.
我们的目标是提出一种新的适用于临床前创新治疗研究的内侧颞叶癫痫发作的按需非人类灵长类动物模型。
对5只猕猴进行立体定向手术，在海马体单侧植入深度记录电极。每次实验时，将青霉素注入海马体，并在连续5小时内对动物进行监测。每只动物共进行了12 - 27次实验，青霉素的平均累积剂量为162644 ± 70190 UI。在98 - 276天的时间里，每周至少重复注射一次。分别从随机选择的84次和11次实验中对电临床发作过程和地西泮的反应进行了量化。为了评估多次青霉素注射所产生的脑损伤并表征海马体中发生的变化，我们进行了组织学分析，包括神经元细胞核和胶质纤维酸性蛋白免疫染色以及电子显微镜检查。
每次注射青霉素后，我们观察到非人类灵长类动物和实验之间的电临床特征具有可重复性。发作持续时间稳定（29.60 ± 6.62秒），发作频率在180分钟内达到平台期，约为每20分钟3次发作，这可能有助于测试新的治疗方法。地西泮并未改变发作过程。发现海马硬化与癫痫患者中遇到的情况相似，存在神经元丢失和胶质细胞增殖。对CA1区的电子显微镜分析显示，注射青霉素的海马体中突触数量减少，且有大量胶质纤维丝。有趣的是，这种按需发作模型在注射累积量为119至145 KIU的青霉素后转变为慢性模型，会自发出现发作。
本研究表明，通过海马体内注射青霉素可以建立内侧颞叶癫痫发作的按需模型。发作具有可重复性、稳定性且对地西泮有抗性。脑损伤局限于海马体，其特征与人类内侧颞叶癫痫中发现的相似。该模型再现了人类内侧颞叶癫痫中通常所见的致症状区和激惹区，另外还有一个优点是能够清晰界定致痫区。然而，青霉素作为惊厥剂的作用机制并未复制人类癫痫中所涉及的所有更为复杂的生理和细胞机制，这是我们研究的一个局限性，必须予以注意。
