Mazengenya Pedzisai, Bhagwandin Adhil, Nkomozepi Pilani, Manger Paul R, Ihunwo Amadi O
School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
Neural Regen Res. 2017 Jul;12(7):1086-1096. doi: 10.4103/1673-5374.211187.
Generation of neurons in the brains of adult birds has been studied extensively in the telencephalon of song birds and few studies are reported on the distribution of PCNA and DCX in the telencephalon of adult non-song learning birds. We report here on adult neurogenesis throughout the brains of two breeds of adult domestic pigeons (Columba livia domestica), the racing homer and utility carneau using endogenous immunohistochemical markers proliferating cell nuclear antigen (PCNA) for proliferating cells and doublecortin (DCX) for immature and migrating neurons. The distribution of PCNA and DCX immunoreactivity was very similar in both pigeon breeds with only a few minor differences. In both pigeons, PCNA and DCX immunoreactivity was observed in the olfactory bulbs, walls of the lateral ventricle, telencephalic subdivisions of the pallium and subpallium, diencephalon, mesencephalon and cerebellum. Generally, the olfactory bulbs and telencephalon had more PCNA and DCX cells than other regions. Two proliferative hotspots were evident in the dorsal and ventral poles of the lateral ventricles. PCNA- and DCX-immunoreactive cells migrated radially from the walls of the lateral ventricle into the parenchyma. In most telencephalic regions, the density of PCNA- and DCX-immunoreactive cells increased from rostral to caudal, except in the mesopallium where the density decreased from rostral to middle levels and then increased caudally. DCX immunoreactivity was more intense in fibres than in cell bodies and DCX-immunoreactive cells included small granular cells, fusiform bipolar cells, large round and or polygonal multipolar cells. The similarity in the distribution of proliferating cells and new neurons in the telencephalon of the two breeds of pigeons may suggest that adult neurogenesis is a conserved trait as an ecological adaptation irrespective of body size.
成年鸟类大脑中神经元的生成在鸣禽的端脑中已得到广泛研究，而关于成年非鸣禽学习鸟类端脑中增殖细胞核抗原（PCNA）和双皮质素（DCX）分布的研究报道较少。我们在此报告使用内源性免疫组织化学标记物对两种成年家鸽（Columba livia domestica），即赛鸽和实用卡诺鸽的全脑成年神经发生情况进行研究，其中增殖细胞核抗原（PCNA）用于标记增殖细胞，双皮质素（DCX）用于标记未成熟和迁移的神经元。两种鸽品种中PCNA和DCX免疫反应性的分布非常相似，仅有一些细微差异。在两种鸽子中，在嗅球、侧脑室壁、大脑皮质和皮质下脑的端脑分区、间脑、中脑和小脑中均观察到PCNA和DCX免疫反应性。一般来说，嗅球和端脑比其他区域有更多的PCNA和DCX细胞。在侧脑室的背侧和腹侧极有两个增殖热点明显可见。PCNA和DCX免疫反应性细胞从侧脑室壁呈放射状迁移到实质中。在大多数端脑区域，PCNA和DCX免疫反应性细胞的密度从吻侧到尾侧增加，但在中脑皮质中，密度从吻侧到中间水平下降，然后在尾侧增加。DCX免疫反应性在纤维中比在细胞体中更强，DCX免疫反应性细胞包括小颗粒细胞、梭形双极细胞、大圆形和/或多边形多极细胞。两种鸽品种端脑中增殖细胞和新神经元分布的相似性可能表明，成年神经发生作为一种生态适应，是一种保守特征，与体型无关。
