A Modification to a Murine Model for Intracranial Aneurysm Formation and Rupture

Current Mouse Models of Intracranial Aneurysms: Analysis of Pharmacological Agents Used to Induce Aneurysms and Their Impact on Translational Research

Intracranial aneurysms (IAs) are rare vascular lesions that are more frequently found in women. The pathophysiology behind the formation and growth of IAs is complex. Hence, to date, no single pharmacological option exists to treat them. Animal models, especially mouse models, represent a valuable tool to explore such complex scientific questions. Genetic modification in a mouse model of IAs, including deletion or overexpression of a particular gene, provides an excellent means for examining basic mechanisms behind disease pathophysiology and developing novel pharmacological approaches. All existing animal models need some pharmacological treatments, surgical interventions, or both to develop IAs, which is different from the spontaneous and natural development of aneurysms under the influence of the classical risk factors. The benefit of such animal models is the development of IAs in a limited time. However, clinical translation of the results is often challenging because of the artificial course of IA development and growth. Here, we summarize the continuous improvement in mouse models of IAs. Moreover, we discuss the pros and cons of existing mouse models of IAs and highlight the main translational roadblocks and how to improve them to increase the success of translational IA research.

How to create a nervous system aneurysm model in canines? ligation of the lingual artery is a simple and effective method

Background: The purpose of this research was to establish a safe, effective, and simple nervous system aneurysm model. This method could quickly and stably establish an exact canine tongue aneurysm model. This paper summarizes the technique and key points of the method. Methods: Under the condition of anesthesia by inhaling isoflurane with a mask, we punctured the femoral artery of the canine, and the tip of the catheter was placed in the common carotid artery for intracranial arteriography. The positions of the lingual artery, external carotid artery, and internal carotid artery were identified. Then, the skin near the mandible was cut according to the positioning and separated layer by layer until the bifurcation of the lingual artery and external carotid artery was exposed. The lingual artery were then sutured with 2-0 silk sutures approximately 3 mm from the external carotid/lingual artery bifurcation. The final angiographic review showed that the aneurysm model was successfully established. Results: The lingual artery aneurysm was successfully established in all 8 canines. All canines obtained a stable model of nervous system aneurysm and confirmed by DSA angiography. Conclusion: We have established a safe, effective, stable and simple method to establish a canine nervous system aneurysm model with controllable size. In addition, this method has the advantages of no arteriotomy, less trauma, constant anatomical location, and low risk of stroke.

Modified Protocol for Establishment of Intracranial Arterial Dolichoectasia Model by Injection of Elastase Into Cerebellomedullary Cistern in Mice

Background and Purpose

This study aimed to construct an animal model of intracranial arterial dolichoectasia (IADE) applying the modified modeling protocol.

Materials and Methods

Twenty five milliunits elastase and inactivated elastase were, respectively, injected into the cerebellomedullary cistern of 60 C57/BL6 mice which were divided into experimental group (EG, n = 30) and control group (CG, n = 30) by using a computer-based random order generator. The modified modeling protocol clarified these aspects including brain three-dimensional parameters of mouse head fixation, angle of head inclination, fixed position of taper ear, needle holding technique, needle entry depth, prevention of liquid drug back flow, and storage conditions of elastase. And it was observed for the following parts such as mortality, inflammatory factors, craniocerebral arteries scanning, vascular tortuosity index, artery diameter, pathology of the cerebrovascular.

Results

Within differently surveyed stage, the total mortality of mice in EG was 20%. ELISA illustrated that the levels of matrix metalloproteinase-9 (MMP-9) and tumor necrosis factor α (TNF-α) in peripheral blood were increased significantly after modeling. Angiography indicated that 100% of IADE in EG were observed and the diameter and tortuosity index of the basilar artery were significantly increased (P < 0.01). EVG histological processing and staining showed the disrupted internal elastic lamina, the atrophied muscle layer, and the hyalinized connective tissue of the basilar artery with the vascular wall tunica media in EG. Micro-computed tomography reported that the craniocerebral arteries of the mice in EG were outstandingly elongated, tortuous, and dilated.

Conclusion

The modified modeling protocol can reduce the mortality, improve the success rate, and provide a stable animal model for IADE.

Beyond Classic Anastomoses Training Models: Overview of Aneurysm Creation in Rodent Vessel Model

Nowadays, due to the decline in the number of microsurgical clippings for cerebral aneurysms and revascularization procedures, young neurosurgeons have fewer opportunities to participate and train on this type of surgery. Vascular neurosurgery is a demanding subspecialty that requires skills that can only be acquired with technical experience. This background pushes the new generations to be ready for such challenging cases by training hard on different available models, such as synthetic tubes, chicken wings, or placenta vessels. Although many training models for vascular neurosurgery have been described worldwide, one of the best is the rodent vessels model. It offers pulsation, coagulation, and real blood flow conditions in a physiologic atmosphere that mimics perfectly the intracranial human vessels environment, especially in terms of size. However, the current differences in governmental different regulations about the use of living animals in medical experimentation and the social awareness, as well as the lack of financial support, cause more difficulties for neurosurgeons to start with that kind of training. In this review, we describe the tools and techniques as basic steps for vascular microsurgery training by using rodent models, that provide an accurate copy of brain vessels environment under stable conditions. The initial three classical known microanastomoses for neurosurgeons are end-to-end, end-to-side, and side-to-side, but in literature, there have been described other more complex exercises for training and investigation, such as aneurysm models. Although there is still little data available, we aim to summarize and discuss aneurysm's training models and reviewed the current literature on the subject and its applications, including a detailed description of the techniques.