Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 268, 8057 Zurich, Switzerland.
Vet J. 2013 Oct;198(1):131-40. doi: 10.1016/j.tvjl.2013.07.029. Epub 2013 Aug 26.
Apoptosis is critical for embryonic development, maintenance of tissue homeostasis and protection against malignant transformation. The Bcl-2 family of proteins plays a key role in intrinsic apoptosis by controlling the integrity of the outer mitochondrial membrane, and the multidomain pro-apoptotic Bcl-2 family members Bax and Bak are essential components of this pathway. The aim of this study was to provide data on the expression of these proteins in normal canine tissues. Two antibodies against Bax recognising different conformations of the protein and one antibody against Bak were validated by immunohistochemistry and immunoblotting using canine recombinant proteins and keratinocytes treated with ultraviolet light. The antibodies were used immunohistochemically to label a wide panel of histologically normal tissues assembled on tissue microarrays. In addition, a subset of the tissues was evaluated by Western blot analysis. Immunohistochemical and Western blot analyses revealed that both Bax and Bak are widely expressed in non-neoplastic tissues from adult dogs. Immunohistochemistry showed almost exclusively cytoplasmic labelling and prominent labelling of epithelial cells. In lymph nodes, immunohistochemical labelling was diffuse for both proteins and showed enhanced intensities in the mantle zones for Bax and the germinal centres for Bak. Strong reactivity for the active conformation of Bax was detected only in enterocytes and Leydig cells and in scattered lymphocytes. These data indicate widespread expression of Bax and Bak in normal canine tissues. Knowledge of the expression of Bax and Bak in normal tissues is a prerequisite in assessing the role of these proteins in canine neoplastic disease.
细胞凋亡对于胚胎发育、组织内稳态的维持以及防止恶性转化至关重要。Bcl-2 蛋白家族通过控制外线粒体膜的完整性在细胞内凋亡中发挥关键作用，多结构域促凋亡 Bcl-2 家族成员 Bax 和 Bak 是该途径的基本组成部分。本研究旨在提供这些蛋白在正常犬组织中表达的相关数据。使用犬重组蛋白和经紫外线处理的角朊细胞，通过免疫组织化学和免疫印迹法对两种针对 Bax 的识别蛋白不同构象的抗体以及一种针对 Bak 的抗体进行了验证。这些抗体通过免疫组织化学用于标记组织微阵列上广泛的组织学正常组织。此外，通过 Western blot 分析评估了其中一部分组织。免疫组织化学和 Western blot 分析显示，Bax 和 Bak 在成年犬的非肿瘤组织中广泛表达。免疫组织化学显示几乎仅为细胞质标记，上皮细胞的标记明显。在淋巴结中，两种蛋白的免疫组织化学标记均为弥漫性，Bax 的帽状带和 Bak 的生发中心增强。仅在肠上皮细胞和莱迪希细胞以及散在的淋巴细胞中检测到 Bax 活性构象的强反应性。这些数据表明 Bax 和 Bak 在正常犬组织中广泛表达。了解 Bax 和 Bak 在正常组织中的表达是评估这些蛋白在犬肿瘤疾病中作用的前提。
