不同年龄牦牛肾的组织学特征

Histological Study on Age-Associated Changes in the Kidney of the Yak

旨在探究牦牛肾的组织学特征及增龄性变化。选取新生(1~7日龄)、成年(3~6岁)及老年(7~10岁)牦牛肾为研究对象,各5头份,采用组织学方法对不同年龄牦牛肾的组织结构进行观察,通过图像分析软件分析并测量肾单位的相关数据。组织学观察显示牦牛肾包含表面的被膜和内部的实质。肾小体由肾小球和肾小囊构成,肾小囊壁层富含胶原纤维,肾小体基膜呈PAS阳性;肾小管包括近端小管和远端小管,其小管外围富含胶原纤维,上皮基膜呈PAS阳性。测量结果表明,单位视野(2.3×10~6μm^2)内肾小球数随年龄增长而减少;肾小球内细胞数和肾小球细胞核大小随年龄增长而增加;不同的是,肾小球和肾小体的最大切面面积,成年达峰值,老年次之,新生最低。另外,随年龄增长,单位视野(2.3×10~4μm^2)内肾皮质与髓质肾小管上皮细胞数,近端小管上皮细胞核的大小,远端小管上皮细胞核的大小分别与单位视野内肾小球个数、肾小球内细胞数和肾小球细胞核的大小、肾小球和肾小体的最大切面面积变化趋势一致。结果表明,牦牛肾的组织结构随年龄的增长出现差异性变化,推测这种变化可能与肾小球硬化、实质性细胞减少有关,具体机制还有待进一步研究。

This experiment was conducted to investigate the histological characteristics and age-related changes in yak kidney. Newborn （1-7 days old, n=5）, adult （3-6 years old, n=5） and old （7-10 years old, n=5） yaks were selected as the subjects, and histological and statistical methods were used to observe the changes in yak kidney. The relevant data of kidney units was analyzed and measured by the image analysis software. Histological observations showed that yak kidneys consisted of the surface of the membrane and the internal substance. The malpighian corpuscles were composed of glomeruli and renal capsules. The wall of the renal capsule was rich in collagen fibers and the basal membrane of malpighian corpuscles was PAS positive. The kidney tubules included proximal tubules and distal tubules, which are rich in collagen fibers and had a positive PAS on the epithelium basal membrane. The results of measuring showed that the number of glomeruli per unit field （2.3×106 μm2） decreased with age; while the number of glomerular cells and the size of glomerular nuclei increased with age; the differences was in the maximum cross-sectional area of glomeruli and malpighian corpuscle were the largest in adult, followed by the differences in the aged, with those in the newborn being the smallest. In addition, with the age increasing, the trend of changes in the number of tubule epithelial cells in the kidney cortex and medulla per unit field （2.3×104 μm2）, the size of proximal tubule and distal tubule epithelial nuclei were the same as the number of glomeruli and cells in glomeruli, the size of glomeruli nuclei, and the maximum cross-sectional area changes of glomeruli and malpighian corpuscle. The results suggested that the histological structures of yak kidney changed with the increase of age. Moreover, it is presumed that the contributing factors to this change might include glomeruli sclerosis and reduction of substantial cells, however, further empirical investigation is required to be conclusive.