Wideman R F
Department of Poultry Science, Pennsylvania State University, University Park 16802.
J Morphol. 1989 Aug;201(2):205-13. doi: 10.1002/jmor.1052010209.
Previous histological evaluations of chick kidneys indicated nephrons continue to develop from embryonic foci for up to 6 weeks after hatching. The present study was conducted using an in vivo alcian blue staining technique to quantify posthatch changes in glomerular numbers and sizes in female domestic fowl at 1, 3, 5, 9, 12, 21, and 30 weeks of age. Changes in glomerular size distributions reflect changes in the heterogeneous nephron populations of avian kidneys. Foci of embryonic tissue were observed at the periphery of renal lobules up to 12 weeks of age. Glomerular numbers increased from 69,800/kidney at 1 week to 586,000/kidney at 12 weeks, with no further significant increase up to 30 weeks (599,000/kidney). The increase in glomerular number per gram kidney weight remained constant as kidney mass increased up to 12 weeks of age, after which the number of glomeruli per gram kidney weight declined significantly as kidney size increased without further addition of new nephrons. Glomerular size distribution profiles were constructed using eleven circumference categories. The peak number of glomeruli fell within the 0.11-0.14 mm category at 1 and 3 weeks; within the 0.15-0.18 mm category at 5, 9, and 12 weeks; and within the 0.19-0.22 mm category at 21 and 30 weeks. One and 3-week-old chicks had no glomeruli within the largest (greater than or equal to 0.35 mm circumference) size categories, and 9-12-week-old birds had significantly fewer glomeruli in these categories than 21-30-week-old birds. These results demonstrate that posthatch renal maturation in domestic fowl involves the ongoing formation of new nephrons up to 12 weeks of age, with subsequent kidney growth (12-30 weeks of age) accomplished by enlargement of existing nephrons (nephron hypertrophy). The cumulative evidence indicates that nephrons destined to develop loops of Henle (mammalian-type) develop first, with shorter (reptilian-type) nephrons developing later as the kidneys enlarge.
先前对雏鸡肾脏的组织学评估表明，孵化后长达6周的时间里，肾单位持续从胚胎病灶发育而来。本研究采用体内阿尔新蓝染色技术，对1、3、5、9、12、21和30周龄雌性家鸡孵化后肾小球数量和大小的变化进行量化。肾小球大小分布的变化反映了禽类肾脏中异质性肾单位群体的变化。在12周龄之前，在肾小叶周边观察到胚胎组织病灶。肾小球数量从1周龄时的69,800个/肾增加到12周龄时的586,000个/肾，直至30周龄（599,000个/肾）均无进一步显著增加。在12周龄之前，随着肾脏质量增加，每克肾脏重量的肾小球数量增加保持恒定，之后随着肾脏大小增加而无新肾单位进一步添加，每克肾脏重量的肾小球数量显著下降。使用11个周长类别构建肾小球大小分布曲线。1周龄和3周龄时，肾小球数量峰值出现在0.11 - 0.14毫米类别；5周龄、9周龄和12周龄时，出现在0.15 - 0.18毫米类别；21周龄和3周龄时，出现在0.19 - 0.22毫米类别。1周龄和3周龄的雏鸡在最大（周长大于或等于0.35毫米）大小类别中没有肾小球，9 - 12周龄的鸡在这些类别中的肾小球数量明显少于21 - 30周龄的鸡。这些结果表明，家鸡孵化后肾脏成熟涉及到12周龄之前新肾单位的持续形成，随后肾脏生长（12 - 30周龄）通过现有肾单位增大（肾单位肥大）来完成。累积证据表明，注定要发育出亨氏袢（哺乳动物型）的肾单位首先发育，随着肾脏增大，较短的（爬行动物型）肾单位随后发育。
