Wang T, Cui Y, Liu P, He J, Zhang Q
Faculty of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China.
Folia Morphol (Warsz). 2019;78(1):114-123. doi: 10.5603/FM.a2018.0067. Epub 2018 Aug 14.
Kidney has long been thought to be a body's largest organ of elimination for maintaining acid-base balance. In recent years, the research on kidneys has mainly focused on the structural characteristics of the kidney of single age group animals. In this paper we used histological and immunohistochemical methods to observe and compare the structure characteristics of yak kidney and the expression of epidermal growth factor receptor (EGFR), bone morphogenetic protein-2 (BMP-2) and p53 in the kidney of yaks of three different age groups. The aim of the study was to investigate histological characteristics of age-related chan- ges in the kidney of yak and expression and localisation of kidney-related factors.
Fifteen healthy male and female yaks from highland plateaus (three groups: newborn, adult and old yaks, n = 5 per group). Histo- logical methods were used to compare the relevant characteristics of the kidney of yaks. The immunohistochemistry method was used to observe the expression and localisation of EGFR, BMP-2, and p53 of the kidney of different ages, and the optical density value was measured and analysed by using image analysis software.
This is an overall observation of the kidney tissue section, which includes the surface of the renal capsule and the internal parenchyma. In the renal parenchyma, there are renal corpuscles, renal tubules. The internal substance included cortex and medulla, which were bounded by the arched artery. In the cortex, there were renal corpuscles, convoluted part of renal tubules (proximal convoluted tubule and distal convoluted tubule) and collecting tubules. The medulla included straight parts of renal tubules (proximal straight tubule and distal straight tubule), thin segments and collecting tubules. It was observed that the organisational structure of the kidney of yaks did not change with age, but the degree of development of the internal structure (glomeruli, renal tubules and collecting tubules) of the kidney changed with age. Immunohistochemical results demonstrated that EGFR and BMP-2-positive reaction in the newborn group was mainly distributed in the proximal tubule epithelial cells, and widely distributed in the adult and old groups. However, the p53-positive reaction was widely distributed in the newborn, adult and old groups.
The results revealed that the kidney structure tended to be com- pleted with age, and the function of the kidney gradually improved. EGFR and BMP-2 had the effect of promoting kidney development. However, p53 had been widely distributed in the newborn kidney of the yaks. It is suggested that p53 had been involved in cell migration and metabolic differentiation and self-renewal in the new stage.
长期以来，肾脏一直被认为是机体维持酸碱平衡的最大排泄器官。近年来，对肾脏的研究主要集中在单一年龄组动物肾脏的结构特征。本文采用组织学和免疫组织化学方法，观察并比较牦牛肾脏的结构特征以及表皮生长因子受体（EGFR）、骨形态发生蛋白-2（BMP-2）和p53在三个不同年龄组牦牛肾脏中的表达情况。本研究旨在探讨牦牛肾脏与年龄相关变化的组织学特征以及肾脏相关因子的表达和定位。
选取15头来自高原地区的健康雌雄牦牛（分为三组：新生牦牛、成年牦牛和老年牦牛，每组n = 5）。采用组织学方法比较牦牛肾脏的相关特征。采用免疫组织化学方法观察不同年龄牦牛肾脏中EGFR、BMP-2和p53的表达及定位，并利用图像分析软件测量和分析光密度值。
这是对肾脏组织切片的整体观察，包括肾被膜表面和内部实质。肾实质内有肾小体、肾小管。内部物质包括皮质和髓质，以弓形动脉为界。皮质内有肾小体、肾小管的曲部（近端小管和远端小管）和集合小管。髓质包括肾小管的直部（近端直小管和远端直小管）、细段和集合小管。观察发现，牦牛肾脏的组织结构不随年龄变化，但肾脏内部结构（肾小球、肾小管和集合小管）的发育程度随年龄变化。免疫组织化学结果显示，新生组EGFR和BMP-2阳性反应主要分布于近端小管上皮细胞，在成年组和老年组广泛分布。然而，p53阳性反应在新生、成年和老年组均广泛分布。
结果表明，肾脏结构随年龄增长趋于完善，肾脏功能逐渐改善。EGFR和BMP-2具有促进肾脏发育的作用。然而，p53在牦牛新生肾脏中已广泛分布。提示p53在新阶段已参与细胞迁移、代谢分化和自我更新。
