Sagol School of Neuroscience, Tel Aviv University, Israel; Neurobiology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel; School of Psychological Sciences, Tel Aviv University, Israel.
Neurobiology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel.
Brain Behav Immun. 2017 May;62:265-276. doi: 10.1016/j.bbi.2017.02.012. Epub 2017 Feb 20.
Blood-borne brain metastases are associated with poor prognosis, but little is known about the interplay between cerebral blood flow, surgical stress responses, and the metastatic process. The intra-carotid inoculation approach, traditionally used in animal studies, involves permanent occlusion of the common carotid artery (CCA). Herein we introduced a novel intra-carotid inoculation approach that avoids CCA ligation, namely - assisted external carotid artery inoculation (aECAi) - and compared it to the traditional approach in C57/BL6 mice, assessing cerebral blood flow; particle distribution; blood-brain barrier (BBB) integrity; stress, inflammatory and immune responses; and brain tumor retention and growth. Doppler flowmetry and two-photon imaging confirmed that only in the traditional approach regional and capillary cerebral blood flux were significantly reduced. Corticosterone and plasma IL-6 levels were higher in the traditional approach, splenic numbers of NK, CD3+, granulocytes, and dendritic cells were lower, and many of these indices were more profoundly affected by surgical stress in the traditional approach. BBB integrity was unaffected. Administration of spherical beads indicated that CCA ligation significantly limited brain distribution of injected particles, and inoculation of D122-LLC syngeneic tumor cells resulted in 10-fold lower brain tumor-cell retention in the traditional approach. Last, while most of the injected tumor cells were arrested in extra-cranial head areas, our method improved targeting of brain-tissue by 7-fold. This head versus brain distribution difference, commonly overlooked, cannot be detected using in vivo bioluminescent imaging. Overall, it is crucial to maintain unperturbed cerebral blood flow while studying brain metastasis and interactions with stress and inflammatory responses.
血源性脑转移与预后不良相关，但对于脑血流、手术应激反应和转移过程之间的相互作用知之甚少。传统上用于动物研究的颈内动脉接种方法涉及颈总动脉（CCA）的永久性闭塞。在此，我们引入了一种新的颈内动脉接种方法，即辅助颈外动脉接种（aECAi），并将其与 C57/BL6 小鼠中的传统方法进行了比较，评估了脑血流；颗粒分布；血脑屏障（BBB）完整性；应激、炎症和免疫反应；以及脑肿瘤保留和生长。多普勒流量测定和双光子成像证实，只有在传统方法中，区域性和毛细血管脑血流才会明显减少。传统方法中皮质酮和血浆 IL-6 水平较高，NK、CD3+、粒细胞和树突状细胞的脾数量较低，其中许多指标在传统方法中受到手术应激的影响更大。BBB 完整性不受影响。球形珠的给药表明 CCA 结扎显著限制了注射颗粒在大脑中的分布，并且接种同源性 D122-LLC 肿瘤细胞导致传统方法中脑肿瘤细胞保留率降低 10 倍。最后，虽然大多数注入的肿瘤细胞被阻滞在颅外头部区域，但我们的方法将大脑组织的靶向性提高了 7 倍。这种头部与大脑的分布差异，通常被忽视，不能通过体内生物发光成像检测到。总体而言，在研究脑转移和与应激及炎症反应的相互作用时，保持脑血流不受干扰至关重要。
